U.S. patent application number 12/725326 was filed with the patent office on 2010-09-16 for showerhead for vapor deposition.
This patent application is currently assigned to ALTA DEVICES, INC.. Invention is credited to Roger Hamamjy, Gang He, Andreas Hegedus, Gregg Higashi, Khurshed Sorabji.
Application Number | 20100229793 12/725326 |
Document ID | / |
Family ID | 42729639 |
Filed Date | 2010-09-16 |
United States Patent
Application |
20100229793 |
Kind Code |
A1 |
He; Gang ; et al. |
September 16, 2010 |
SHOWERHEAD FOR VAPOR DEPOSITION
Abstract
Embodiments of the invention generally relate to apparatuses for
chemical vapor deposition (CVD) processes. In one embodiment, a
showerhead assembly is provided which includes a body having a
centralized channel extending through upper and lower portions of
the body and extending parallel to a central axis of the body. The
showerhead assembly contains an optional diffusion plate having a
first plurality of holes and disposed within the centralized
channel, an upper tube plate having a second plurality of holes and
disposed within the centralized channel below the diffusion plate,
a lower tube plate having a third plurality of holes and disposed
within the centralized channel below the upper tube plate, and a
plurality of tubes extending from the upper tube plate to the lower
tube plate. Each tube is coupled to and in fluid communication with
individual holes of the upper and lower tube plates.
Inventors: |
He; Gang; (Cupertino,
CA) ; Higashi; Gregg; (San Jose, CA) ;
Sorabji; Khurshed; (San Jose, CA) ; Hamamjy;
Roger; (San Jose, CA) ; Hegedus; Andreas;
(Burlingame, CA) |
Correspondence
Address: |
PATTERSON & SHERIDAN, L.L.P.
3040 POST OAK BOULEVARD, SUITE 1500
HOUSTON
TX
77056
US
|
Assignee: |
ALTA DEVICES, INC.
Santa Clara
CA
|
Family ID: |
42729639 |
Appl. No.: |
12/725326 |
Filed: |
March 16, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61160690 |
Mar 16, 2009 |
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61160694 |
Mar 16, 2009 |
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61160696 |
Mar 16, 2009 |
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61160699 |
Mar 16, 2009 |
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61160700 |
Mar 16, 2009 |
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61160701 |
Mar 16, 2009 |
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61160703 |
Mar 16, 2009 |
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Current U.S.
Class: |
118/715 |
Current CPC
Class: |
C23C 16/4583 20130101;
C23C 16/4412 20130101; C23C 16/4557 20130101; C23C 16/45565
20130101; C23C 16/45519 20130101; C23C 16/54 20130101; C23C 16/4411
20130101 |
Class at
Publication: |
118/715 |
International
Class: |
C23C 16/455 20060101
C23C016/455; C23C 16/00 20060101 C23C016/00 |
Claims
1. A showerhead assembly for a vapor deposition chamber,
comprising: a body comprising an upper portion and a lower portion;
a centralized channel extending through the upper and lower
portions of the body, between inner surfaces of the body, and
parallel to a central axis extending through the body; a diffusion
plate comprising a first plurality of holes and disposed within the
centralized channel; an upper tube plate comprising a second
plurality of holes and disposed within the centralized channel
below the diffusion plate; a lower tube plate comprising a third
plurality of holes and disposed within the centralized channel
below the upper tube plate; and a plurality of tubes extending from
the upper tube plate to the lower tube plate, wherein each tube is
coupled to and in fluid communication with an individual hole from
the second plurality of holes and an individual hole from the third
plurality of holes.
2. The showerhead assembly of claim 1, wherein the upper portion
and the lower portion of the body each independently comprises at
least one material selected from the group consisting of steel,
stainless steel, 300 series stainless steel, iron, nickel,
chromium, molybdenum, aluminum, alloys thereof, and combinations
thereof.
3. The showerhead assembly of claim 2, wherein the upper portion
and the lower portion of the body each independently comprises
stainless steel or alloys thereof.
4. The showerhead assembly of claim 1, further comprising a gaseous
inlet disposed on the upper portion of the body.
5. The showerhead assembly of claim 4, further comprising a plate
disposed on an upper surface of the upper portion of the body, and
the gaseous inlet is disposed on the plate.
6. The showerhead assembly of claim 5, wherein the plate comprises
a material selected from the group consisting of steel, stainless
steel, 300 series stainless steel, iron, nickel, chromium,
molybdenum, aluminum, alloys thereof, and combinations thereof.
7. The showerhead assembly of claim 5, wherein the plate comprises
an inlet port extending through the plate.
8. The showerhead assembly of claim 7, wherein the gaseous inlet
comprises an inlet tube extending through the inlet port, and a
nozzle is coupled to one end of the inlet tube and disposed above
the plate.
9. The showerhead assembly of claim 1, wherein an upper surface of
the upper portion of the body comprises a groove which encompasses
the centralized channel, and the groove comprises an O-ring.
10. The showerhead assembly of claim 1, wherein the diffusion plate
is disposed on a ledge protruding from side surfaces of the body
within the centralized channel.
11. The showerhead assembly of claim 1, wherein the plurality of
tubes comprises from about 500 tubes to about 1,500 tubes.
12. The showerhead assembly of claim 11, wherein the plurality of
tubes comprises from about 800 tubes to about 1,000 tubes.
13. The showerhead assembly of claim 1, wherein each tube has a
length within a range from about 0.5 cm to about 2 cm.
14. The showerhead assembly of claim 13, wherein the length is
within a range from about 0.8 cm to about 1.2 cm.
15. The showerhead assembly of claim 1, wherein each tube comprises
a diameter within a range from about 0.005 inches to about 0.05
inches.
16. The showerhead assembly of claim 15, wherein the diameter is
within a range from about 0.01 inches to about 0.03 inches.
17. The showerhead assembly of claim 1, wherein the tubes are
hypodermic needles.
18. The showerhead assembly of claim 1, wherein the tubes comprise
a material selected from the group consisting of steel, stainless
steel, 300 series stainless steel, iron, nickel, chromium,
molybdenum, aluminum, alloys thereof, and combinations thereof.
19. The showerhead assembly of claim 18, wherein the upper portion
and the lower portion of the body each independently comprises
stainless steel or alloys thereof.
20. The showerhead assembly of claim 1, wherein each hole of the
first plurality of holes has a larger diameter than each hole of
the second plurality of holes or each hole of the third plurality
of holes.
21. The showerhead assembly of claim 1, wherein each hole of the
second plurality of holes has the same diameter or substantially
the same diameter as each hole of the third plurality of holes.
22. The showerhead assembly of claim 1, wherein the diffusion plate
comprises a material selected from the group consisting of steel,
stainless steel, 300 series stainless steel, iron, nickel,
chromium, molybdenum, aluminum, alloys thereof, and combinations
thereof.
23. The showerhead assembly of claim 22, wherein the diffusion
plate comprises from about 20 holes to about 200 holes.
24. The showerhead assembly of claim 23, wherein the diffusion
plate comprises from about 40 holes to about 60 holes.
25. The showerhead assembly of claim 23, wherein each hole of the
diffusion plate comprises a diameter within a range from about
0.005 inches to about 0.05 inches.
26. The showerhead assembly of claim 25, wherein the diameter is
within a range from about 0.01 inches to about 0.03 inches.
27. The showerhead assembly of claim 1, wherein each of the upper
tube plate and the lower tube plate independently comprises a
material selected from the group consisting of steel, stainless
steel, 300 series stainless steel, iron, nickel, chromium,
molybdenum, aluminum, alloys thereof, and combinations thereof.
28. The showerhead assembly of claim 27, wherein each of the upper
tube plate and the lower tube plate independently comprises from
about 500 holes to about 1,500 holes.
29. The showerhead assembly of claim 28, wherein each of the upper
tube plate and the lower tube plate independently comprises from
about 800 holes to about 1,000 holes.
30. The showerhead assembly of claim 28, wherein each hole of the
upper tube plate or the lower tube plate independently comprises a
diameter within a range from about 0.005 inches to about 0.05
inches.
31. The showerhead assembly of claim 30, wherein the diameter is
within a range from about 0.01 inches to about 0.03 inches.
32. The showerhead assembly of claim 1, wherein the upper tube
plate and the lower tube plate each independently comprises a
gaseous hole density within a range from about 10 holes/in.sup.2 to
about 60 holes/in.sup.2.
33. The showerhead assembly of claim 1, wherein an upper surface of
the upper portion of the body is a metallic plate.
34. The showerhead assembly of claim 1, further comprising a
temperature regulation system, wherein the temperature regulation
system comprises a fluid passageway extending within the body, the
temperature regulation system comprises an inlet and an outlet
coupled to and in fluid communication with the fluid passageway,
and the inlet and the outlet are independently coupled to and in
fluid communication with a heat exchanger.
35. The showerhead assembly of claim 1, wherein the showerhead
assembly is a modular showerhead assembly configured to be
positioned within a CVD reactor system.
36. The showerhead assembly of claim 1, wherein the body has a
rectangular geometry or a square geometry.
37. The showerhead assembly of claim 1, wherein the upper portion
of the body comprises a flange extending over the lower portion of
the body.
38. A showerhead assembly for a vapor deposition chamber,
comprising: a body comprising an upper portion and a lower portion;
a centralized channel extending through the upper and lower
portions of the body, between inner surfaces of the body, and
parallel to a central axis extending through the body; an upper
tube plate comprising a first plurality of holes and disposed
within the centralized channel below the diffusion plate; a lower
tube plate comprising a second plurality of holes and disposed
within the centralized channel below the upper tube plate; and a
plurality of tubes extending from the upper tube plate to the lower
tube plate, wherein each tube is coupled to and in fluid
communication with an individual hole from the first plurality of
holes and an individual hole from the second plurality of
holes.
39. An exhaust assembly for a vapor deposition chamber, comprising:
a body comprising an upper portion disposed on a lower portion; a
centralized channel extending through the upper and lower portions
of the body, between inner surfaces of the body, and parallel to a
central axis extending through the body; an exhaust outlet disposed
on the upper portion of the body; a diffusion plate comprising a
first plurality of holes and disposed within the centralized
channel; an upper tube plate comprising a second plurality of holes
and disposed within the centralized channel below the diffusion
plate; a lower tube plate comprising a third plurality of holes and
disposed within the centralized channel below the upper tube plate;
and a plurality of tubes extending from the upper tube plate to the
lower tube plate, wherein each tube is coupled to and in fluid
communication with an individual hole from the second plurality of
holes and an individual hole from the third plurality of holes.
40. The exhaust assembly of claim 39, further comprising a plate
disposed on an upper surface of the upper portion of the body, and
the exhaust outlet is disposed on the plate.
41. The exhaust assembly of claim 40, wherein the plate comprises a
material selected from the group consisting of steel, stainless
steel, 300 series stainless steel, iron, nickel, chromium,
molybdenum, aluminum, alloys thereof, and combinations thereof.
42. The exhaust assembly of claim 40, wherein the plate comprises
an exhaust port extending through the plate.
43. The exhaust assembly of claim 42, wherein the exhaust outlet
comprises an exhaust tube extending through the exhaust port.
44. The exhaust assembly of claim 43, wherein an exhaust nozzle is
coupled to one end of the exhaust tube and disposed above the
plate.
45. The exhaust assembly of claim 39, wherein an upper surface of
the upper portion of the body comprises a groove which encompasses
the centralized channel, and the groove comprises an O-ring.
46. The exhaust assembly of claim 39, wherein the diffusion plate
is disposed on a ledge protruding from side surfaces of the body
within the centralized channel.
47. The exhaust assembly of claim 39, wherein the upper tube plate
and the lower tube plate each independently comprises a material
selected from the group consisting of steel, stainless steel, 300
series stainless steel, iron, nickel, chromium, molybdenum,
aluminum, alloys thereof, and combinations thereof.
48. The exhaust assembly of claim 39, wherein the upper tube plate
and the lower tube plate each independently comprises from about 5
holes to about 50 holes.
49. The exhaust assembly of claim 48, wherein the upper tube plate
and the lower tube plate each independently comprises from about 10
holes to about 20 holes.
50. The exhaust assembly of claim 48, wherein each hole of the
upper tube plate and each hole of the lower tube plate
independently comprises a diameter within a range from about 0.1
inches to about 0.4 inches.
51. The exhaust assembly of claim 39, wherein the upper tube plate
and the lower tube plate each independently comprises a gaseous
hole density within a range from about 5 holes/in.sup.2 to about 30
holes/in.sup.2.
52. The exhaust assembly of claim 39, wherein the showerhead
assembly is a modular showerhead assembly configured to be
positioned within a CVD reactor system.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. Provisional
Application Nos. 61/160,690, 61/160,694, 61/160,696, 61/160,699,
61/160,700, 61/160,701, and 61/160,703, all of which were filed
Mar. 16, 2009, and all of which are hereby incorporated by
reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Embodiments of the invention generally relate to apparatuses
and methods for vapor deposition, and more particularly, to
chemical vapor deposition systems, reactors, and processes
thereof.
[0004] 2. Description of the Related Art
[0005] Photovoltaic or solar devices, semiconductor devices, or
other electronic devices are usually manufactured by utilizing a
variety of fabrication processes to manipulate the surface of a
substrate. These fabrication processes may include deposition,
annealing, etching, doping, oxidation, nitridation, and many other
processes. Epitaxial lift off (ELO) is a less common technique for
fabricating thin film devices and materials in which layers of
materials are deposited to and then removed from a growth
substrate. An epitaxial layer, film, or material is grown or
deposited on a sacrificial layer which is disposed on the growth
substrate, such as a gallium arsenide wafer, by a chemical vapor
deposition (CVD) process or a metallic-organic CVD (MOCVD) process.
Subsequently, the sacrificial layer is selectively etched away in a
wet acid bath, while the epitaxial material is separated from the
growth substrate during the ELO etch process. The isolated
epitaxial material may be a thin layer or film which is usually
referred to as the ELO film or the epitaxial film. Each epitaxial
film generally contains numerous layers of varying compositions
relative to the specific device, such as photovoltaic or solar
devices, semiconductor devices, or other electronic devices.
[0006] The CVD process includes growing or depositing the epitaxial
film by the reaction of vapor phase chemical precursors. During a
MOCVD process, at least one of the chemical precursors is a
metallic-organic compound--that is--a compound having a metal atom
and at least one ligand containing an organic fragment.
[0007] There are numerous types of CVD reactors for very different
applications. For example, CVD reactors include single or bulk
wafer reactors, atmospheric and low pressure reactors, ambient
temperature and high temperature reactors, as well as plasma
enhanced reactors. These distinct designs address a variety of
challenges that are encountered during a CVD process, such as
depletion effects, contamination issues, reactor maintenance,
throughput, and production costs.
[0008] Therefore, there is a need for CVD systems, reactors, and
processes to grow epitaxial films and materials on substrates more
effectively with less contamination, higher throughput, and less
expensive than by currently known CVD equipment and processes.
SUMMARY OF THE INVENTION
[0009] Embodiments of the invention generally relate to apparatuses
and methods for chemical vapor deposition (CVD) processes. In
another embodiment, a showerhead assembly for a vapor deposition
chamber is provided which includes a body having an upper portion
and a lower portion, a centralized channel extending through the
upper and lower portions of the body, between inner surfaces of the
body, and parallel to a central axis extending through the body,
and an optional diffusion plate having a first plurality of holes
and disposed within the centralized channel. The showerhead
assembly further has an upper tube plate having a second plurality
of holes and disposed within the centralized channel below the
diffusion plate, a lower tube plate having a third plurality of
holes and disposed within the centralized channel below the upper
tube plate, and a plurality of tubes extending from the upper tube
plate to the lower tube plate, wherein each tube is coupled to and
in fluid communication with an individual hole from the second
plurality of holes and an individual hole from the third plurality
of holes.
[0010] In another embodiment, a showerhead assembly for a vapor
deposition chamber is provided which includes a body containing an
upper portion and a lower portion, wherein the upper portion
contains a flange extending over the lower portion, a centralized
channel extending through the upper and lower portions of the body,
between inner surfaces of the body, and parallel to a central axis
extending through the body, an optional diffusion plate having a
first plurality of holes and disposed within the centralized
channel, an upper tube plate having a second plurality of holes and
disposed within the centralized channel below the diffusion plate,
a lower tube plate having a third plurality of holes and disposed
within the centralized channel below the upper tube plate, and a
plurality of tubes extending from the upper tube plate to the lower
tube plate, wherein each tube is coupled to and in fluid
communication with an individual hole from the second plurality of
holes and an individual hole from the third plurality of holes.
[0011] In another embodiment, a showerhead assembly for a vapor
deposition chamber is provided which includes a body containing an
upper portion and a lower portion, wherein the upper portion
adjacently extends from a central axis of the body further than the
lower portion and the lower portion extends parallel to the central
axis further than the upper portion, a centralized channel
extending through the upper and lower portions of the body, between
inner surfaces of the body, and parallel to the central axis, an
optional diffusion plate having a first plurality of holes and
disposed within the centralized channel, an upper tube plate having
a second plurality of holes and disposed within the centralized
channel below the diffusion plate, a lower tube plate having a
third plurality of holes and disposed within the centralized
channel below the upper tube plate, and a plurality of tubes
extending from the upper tube plate to the lower tube plate,
wherein each tube is coupled to and in fluid communication with an
individual hole from the second plurality of holes and an
individual hole from the third plurality of holes.
[0012] In another embodiment, a showerhead assembly for a vapor
deposition chamber is provided which includes a body containing an
upper portion and a lower portion, a centralized channel extending
through the upper and lower portions of the body, between inner
surfaces of the body, and parallel to a central axis extending
through the body, an optional diffusion plate having a first
plurality of holes and disposed within the centralized channel, an
upper tube plate having a second plurality of holes and disposed
within the centralized channel below the diffusion plate, and a
lower tube plate having a third plurality of holes and disposed
within the centralized channel below the upper tube plate.
[0013] In another embodiment, a showerhead assembly for a vapor
deposition chamber is provided which includes a body containing an
upper portion and a lower portion, a centralized channel extending
through the upper and lower portions of the body, between inner
surfaces of the body, and parallel to a central axis extending
through the body, an upper tube plate having a first plurality of
holes and disposed within the centralized channel below the
diffusion plate, a lower tube plate having a second plurality of
holes and disposed within the centralized channel below the upper
tube plate, and a plurality of tubes extending from the upper tube
plate to the lower tube plate, wherein each tube is coupled to and
in fluid communication with an individual hole from the first
plurality of holes and an individual hole from the second plurality
of holes.
[0014] In some embodiments, the showerhead assembly is a modular
showerhead assembly. The upper portion and the lower portion of the
body showerhead assembly may independently contain a material such
as steel, stainless steel, 300 series stainless steel, iron,
nickel, chromium, molybdenum, aluminum, alloys thereof, or
combinations thereof. In one example, the upper portion and the
lower portion of the body each independently contains stainless
steel or alloys thereof.
[0015] In one embodiment, the showerhead assembly contains a
gaseous inlet disposed on the upper portion of the body. A plate
may be disposed on an upper surface of the upper portion of the
body and the gaseous inlet may be disposed on the plate. The plate
may contain a material such as steel, stainless steel, 300 series
stainless steel, iron, nickel, chromium, molybdenum, aluminum,
alloys thereof, or combinations thereof. In some examples, the
plate has an inlet port extending therethrough. The gaseous inlet
has an inlet tube extending through the inlet port. A nozzle may be
coupled to one end of the inlet tube and disposed above the plate.
In another example, the upper surface of the upper portion of the
showerhead body has a groove which encompasses the centralized
channel. An O-ring may be disposed within the groove. The diffusion
plate may be disposed on a ledge or a flange protruding from side
surfaces of the body within the centralized channel.
[0016] In one embodiment, the plurality of tubes may have tubes
numbering within a range from about 500 tubes to about 1,500 tubes,
preferably, from about 700 tubes to about 1,200 tubes, and more
preferably, from about 800 tubes to about 1,000 tubes. In some
examples, each tube may have a length within a range from about 0.5
cm to about 2 cm, preferably, from about 0.8 cm to about 1.2 cm,
for example, about 1 cm. In other examples, each tube may have a
diameter within a range from about 0.005 inches to about 0.05
inches, preferably, from about 0.01 inches to about 0.03 inches. In
some examples, the tubes are hypodermic needles. The tubes may
contain or be made from a material such as steel, stainless steel,
300 series stainless steel, iron, nickel, chromium, molybdenum,
aluminum, alloys thereof, or combinations thereof.
[0017] In one embodiment, each hole of the first plurality of holes
on the diffusion plate has a larger diameter than each hole of the
second plurality of holes on the upper tube plate. Further, each
hole of the first plurality of holes on the diffusion plate has a
larger diameter than each hole of the third plurality of holes on
the lower diffusion plate. Also, each hole of the second plurality
of holes on the upper tube plate has the same diameter or
substantially the same diameter as each hole of the third plurality
of holes on the lower tube plate.
[0018] In one embodiment, the diffusion plate may contain or be
made from a material such as steel, stainless steel, 300 series
stainless steel, iron, nickel, chromium, molybdenum, aluminum,
alloys thereof, or combinations thereof. The diffusion plate may
contain holes numbering within a range from about 20 holes to about
200 holes, preferably, from about 25 holes to about 75 holes, and
more preferably, from about 40 holes to about 60 holes. Each hole
of the diffusion plate may have a diameter within a range from
about 0.005 inches to about 0.05 inches, preferably, from about
0.01 inches to about 0.03 inches. In another embodiment, the upper
tube plate and/or the lower tube plate may independently contain or
be independently made from a material such as steel, stainless
steel, 300 series stainless steel, iron, nickel, chromium,
molybdenum, aluminum, alloys thereof, or combinations thereof. The
upper tube plate and/or the lower tube plate may independently have
from about 500 holes to about 1,500 holes, preferably, from about
700 holes to about 1,200 holes, and more preferably, from about 800
holes to about 1,000 holes. Each hole of the upper tube plate
and/or the lower tube plate may independently have a diameter
within a range from about 0.005 inches to about 0.05 inches,
preferably, from about 0.01 inches to about 0.03 inches.
[0019] In one example, the upper surface of the upper portion of
the body of the showerhead assembly is a metallic plate. In other
examples, the showerhead assembly body may have a rectangular
geometry or a square geometry. In another embodiment, the body of
the showerhead assembly further contains a temperature regulation
system. The temperature regulation system may have a fluid
passageway extending within the body, and may have an inlet and an
outlet coupled to and in fluid communication with the fluid
passageway. The inlet and the outlet may be independently coupled
to and in fluid communication with a liquid reservoir, a heat
exchanger, or multiple heat exchangers.
[0020] In other embodiments, an exhaust assembly for a vapor
deposition chamber is provided which includes a body containing an
upper portion disposed on a lower portion, a centralized channel
extending through the upper and lower portions of the body, between
inner surfaces of the body, and parallel to a central axis
extending through the body, an exhaust outlet disposed on the upper
portion of the body, an optional diffusion plate having a first
plurality of holes and disposed within the centralized channel, an
upper tube plate having a second plurality of holes and disposed
within the centralized channel below the diffusion plate, a lower
tube plate having a third plurality of holes and disposed within
the centralized channel below the upper tube plate, and a plurality
of tubes extending from the upper tube plate to the lower tube
plate, wherein each tube is coupled to and in fluid communication
with an individual hole from the second plurality of holes and an
individual hole from the third plurality of holes.
[0021] The exhaust assembly may further contain a plate disposed on
an upper surface of the upper portion of the body. The exhaust
outlet may be disposed on the plate. The plate may contain or be
made from a material such as steel, stainless steel, 300 series
stainless steel, iron, nickel, chromium, molybdenum, aluminum,
alloys thereof, or combinations thereof. The plate usually has an
exhaust port extending therethrough. The exhaust outlet may have an
exhaust tube extending through the exhaust port. In one example, an
exhaust nozzle may be coupled to one end of the exhaust tube and
disposed above the plate. In another example, the upper surface of
the upper portion of the exhaust assembly body has a groove which
encompasses the centralized channel. An O-ring or other spacer may
be disposed within the groove. The diffusion plate may be disposed
on a ledge or a flange protruding from side surfaces of the body
within the centralized channel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] So that the manner in which the above recited features of
the invention can be understood in detail, a more particular
description of the invention, briefly summarized above, may be had
by reference to embodiments, some of which are illustrated in the
appended drawings. It is to be noted, however, that the appended
drawings illustrate only typical embodiments of this invention and
are therefore not to be considered limiting of its scope, for the
invention may admit to other equally effective embodiments.
[0023] FIGS. 1A-1E depict a CVD reactor according to embodiments
described herein;
[0024] FIG. 1F depicts a CVD reactor coupled to a temperature
regulation system according to another embodiment described
herein;
[0025] FIGS. 2A-2C depict a reactor lid assembly according to
embodiments described herein;
[0026] FIG. 2D depicts a reactor lid support according to an
embodiment described herein;
[0027] FIG. 3 depicts a reactor body assembly according to
embodiments described herein;
[0028] FIGS. 4A-4E depict a wafer carrier track according to
embodiments described herein;
[0029] FIGS. 5A-5D depict an isolator assembly according to
embodiments described herein;
[0030] FIG. 6 depicts a heating lamp assembly according to
embodiments described herein;
[0031] FIGS. 7A-7D depict a showerhead assembly according to
embodiments described herein;
[0032] FIGS. 8A-8D depict an exhaust assembly according to
embodiments described herein;
[0033] FIGS. 9A-9F depict a CVD system containing multiple CVD
reactors according to embodiments described herein;
[0034] FIGS. 10A-10B depict lamps according to embodiments
described herein;
[0035] FIGS. 11A-11F depict a plurality of lamps according to other
embodiments described herein;
[0036] FIGS. 12A-12B depict a levitating substrate carrier
according to another embodiment described herein; and
[0037] FIGS. 12C-12E depict other levitating substrate carriers
according to another embodiment described herein.
DETAILED DESCRIPTION
[0038] Embodiments of the invention generally relate to an
apparatus and methods of chemical vapor deposition (CVD), such as
metallic-organic CVD (MOCVD) processes. As set forth herein,
embodiments of the invention are described as they relate to an
atmospheric pressure CVD reactor and metal-organic precursor gases.
It is to be noted, however, that aspects of the invention are not
limited to use with an atmospheric pressure CVD reactor or
metal-organic precursor gases, but are applicable to other types of
reactor systems and precursor gases. To better understand the
novelty of the apparatuses of the invention and the methods of use
thereof, reference is hereafter made to the accompanying
drawings.
[0039] According to one embodiment of the invention, an atmospheric
pressure CVD reactor is provided. The CVD reactor may be used to
provide multiple epitaxial layers on a substrate, such as a gallium
arsenide substrate. These epitaxial layers may include aluminum
gallium arsenide, gallium arsenide, and phosphorous gallium
arsenide. These epitaxial layers may be grown on the gallium
arsenide substrate for later removal so that the substrate may be
reused to generate additional materials. In one embodiment, the CVD
reactor may be used to provide solar cells. These solar cells may
further include single junction, hetero-junction, or other
configurations. In one embodiment, the CVD reactor may be
configured to develop a 2.5 watt wafer on a 10 centimeter by 10
centimeter substrate. In one embodiment, the CVD reactor may
provide a throughput range of about 1 substrate per minute to about
10 substrates per minute.
[0040] FIGS. 1A-1E depict reactor 100, a CVD reactor or chamber, as
described in an embodiment described herein. Reactor 100 contains
reactor lid assembly 200 disposed on reactor body assembly 102.
Reactor lid assembly 200 and components thereof are further
illustrated in FIGS. 2A-2D and reactor body assembly 102 is further
illustrated in FIG. 3.
[0041] Reactor lid assembly 200 contains an injector or isolator,
isolator assembly 500, disposed between two showerheads, showerhead
assemblies 700. Reactor lid assembly 200 also contains exhaust
assembly 800. FIG. 1C depicts reactor 100 containing two deposition
stations, such as chamber stations 160, 162. Chamber station 160
contains showerhead assembly 700 and isolator assembly 500 while
chamber station 162 contains showerhead assembly 700 and exhaust
assembly 800. In one embodiment, isolator assembly 500 may be used
to flow gas to separate both showerhead assemblies 700 from each
other, while exhaust assembly 800 may be used to isolate the
internal environment of reactor 100 from another reactor connected
to faceplate 112.
[0042] In many embodiments described herein, each of the showerhead
assemblies 700 may be a modular showerhead assembly, each of the
isolator assemblies 500 may be a modular isolator assembly, and
each of the exhaust assemblies 800 may be a modular exhaust
assembly. Any of the showerhead assemblies 700, the isolator
assemblies 500, and/or the exhaust assemblies 800 may be removed
from reactor lid assembly 200, and replaced with the same or a
different assembly as desired for the particular process
conditions. The modular assemblies of the showerhead assemblies
700, the isolator assemblies 500, and/or the exhaust assemblies 800
may independently be configured for positioning within a CVD
reactor system.
[0043] In alternative embodiments described herein, other
configurations of reactor 100 are provided, but not illustrated in
the drawings. In one embodiment, reactor lid assembly 200 of
reactor 100 contains three exhaust assemblies 800 separated by two
showerhead assemblies 700 so that reactor lid assembly 200
sequentially contain a first exhaust assembly, a first showerhead
assembly, a second exhaust assembly, a second showerhead assembly,
and a third exhaust assembly. In another embodiment, reactor lid
assembly 200 of reactor 100 contains three isolator assemblies 500
separated by two showerhead assemblies 700 so that reactor lid
assembly 200 sequentially contain a first isolator assembly, a
first showerhead assembly, a second isolator assembly, a second
showerhead assembly, and a third isolator assembly.
[0044] In another embodiment, reactor lid assembly 200 of reactor
100 contains two isolator assemblies 500 and one exhaust assembly
800 separated by two showerhead assemblies 700 so that reactor lid
assembly 200 sequentially contains a first isolator assembly, a
first showerhead assembly, a second isolator assembly, a second
showerhead assembly, and a first exhaust assembly. In another
example, reactor lid assembly 200 may sequentially contain a first
isolator assembly, a first showerhead assembly, a first exhaust
assembly, a second showerhead assembly, and a second isolator
assembly. In another example, reactor lid assembly 200 may
sequentially contain a first exhaust assembly, a first showerhead
assembly, a first isolator assembly, a second showerhead assembly,
and a second isolator assembly.
[0045] In another embodiment, reactor lid assembly 200 of reactor
100 contains two exhaust assemblies 800 and one isolator assembly
500 separated by two showerhead assemblies 700 so that reactor lid
assembly 200 sequentially contains a first exhaust assembly, a
first showerhead assembly, a second exhaust assembly, a second
showerhead assembly, and a first isolator assembly. In another
example, reactor lid assembly 200 may sequentially contain a first
exhaust assembly, a first showerhead assembly, a first isolator
assembly, a second showerhead assembly, and a second exhaust
assembly. In another example, reactor lid assembly 200 may
sequentially contain a first isolator assembly, a first showerhead
assembly, a first exhaust assembly, a second showerhead assembly,
and a second exhaust assembly.
[0046] Reactor body assembly 102 contains faceplate 110 on one end
and faceplate 112 on the opposite end. Faceplates 110 and 112 may
each independently be utilized to couple together additional
reactors, similar or different than reactor 100, or to couple an
end cap, an end plate, a wafer/substrate handler, or another
device. In one example, faceplate 110 of reactor 100 may be coupled
to faceplate 112 of another reactor (not shown). Similar, faceplate
112 of reactor 100 may be coupled to faceplate 110 of another
reactor (not shown). A seal, spacer, or O-ring may be disposed
between two joining faceplates. In one embodiment, the seal may
contain a metal, such as nickel or a nickel alloy. In one example,
the seal is a knife edge metal seal. In another embodiment, the
seal contains a polymer or an elastomer, such as a KALREZ.RTM.
elastomer seal, available from DuPont Performance Elastomers L.L.C.
In another embodiment, the seal may be a helix seal or an H-seal.
The seal or O-ring should form a gas tight seal to prevent, or
greatly reduce ambient gas from entering reactor 100. Reactor 100
may be maintained with little or no oxygen, water, or carbon
dioxide during use or production. In one embodiment, reactor 100
may be maintained with an oxygen concentration, a water
concentration, and/or a carbon dioxide concentration independently
of about 100 ppb (parts per billion) or less, preferably, about 10
ppb or less, more preferably, about 1 ppb or less, and more
preferably, about 100 ppt (parts per trillion) or less.
[0047] Sides 120 and 130 extend along the length of reactor body
assembly 102. Side 120 has upper surface 128 and side 130 has upper
surface 138. Upper surfaces 114 and 116 of reactor body assembly
102 extend between upper surfaces 128 and 138. Upper surface 114 is
on reactor body assembly 102 just inside and parallel to faceplate
110 and upper surface 116 is on reactor body assembly 102 just
inside and parallel to faceplate 112. Gas inlet 123 is coupled to
and extends from side 120. The levitation gas or carrier gas may be
administered into reactor 100 through gas inlet 123. The levitation
gas or carrier gas may contain nitrogen, helium, argon, hydrogen,
or mixtures thereof.
[0048] FIG. 1F depicts reactor 100, including reactor body assembly
102 and reactor lid assembly 200, coupled to temperature regulation
system 190, according to one embodiment described herein.
Temperature regulation system 190 is illustrated in FIG. 1F as
having three heat exchangers 180a, 180b, and 180c. However,
temperature regulation system 190 may have 1, 2, 3, 4, 5, or more
heat exchangers coupled to and in fluid communication with the
various portions of reactor 100. Each of the heat exchangers 180a,
180b, or 180c may contain at least one liquid supply 182 and at
least one liquid return 184. Each liquid supply 182 may be coupled
to and in fluid communication with inlets on reactor 100 by conduit
186 while each liquid return 184 may be coupled to and in fluid
communication with outlets on reactor 100 by conduit 186. Conduits
186 may include pipes, tubing, hoses, other hollow lines, or
combinations thereof. Valve 188 may be used on each conduit 186
between liquid supply 182 and an inlet or between liquid return 184
and an outlet.
[0049] Reactor body assembly 102 is coupled to and in fluid
communication with at least one heat exchanger as part of the heat
regulation system. In some embodiments, reactor body assembly 102
may be coupled to and in fluid communication with two, three, or
more heat exchangers. FIG. 1B depicts inlet 118a and outlet 118b
coupled to and in fluid communication with lower portion 104 of
reactor 100 and with the heat regulation system.
[0050] In one embodiment, inlets 122a, 122b, and 122c, and outlets
126a, 126b, and 126c are coupled to and extend from side 120. At
least one heat exchanger is coupled to and in fluid communication
with inlets 122a, 122b, and 122c, and outlets 126a, 126b, and 126c.
Inlets 122a, 122b, and 122c may receive a liquid from the heat
exchangers while outlets 126a, 126b, and 126c send the liquid back
to the heat exchanger. In one embodiment, each inlet 122a, 122b, or
122c is positioned in a lower position than each respective outlet
126a, 126b, or 126c, so that flowing liquid from each inlet 122a,
122b, or 122c upwardly flows through each connecting passageway to
each respective outlet 126a, 126b, or 126c.
[0051] In another embodiment, inlets 132a, 132b, and 132c, and
outlets 136a, 136b, and 136c are coupled to and extend from side
130. At least one heat exchanger is coupled to and in fluid
communication with inlets 132a, 132b, and 132c, and outlets 136a,
136b, and 136c. Inlets 132a, 132b, and 132c may receive a liquid
from the heat exchanger while outlets 136a, 136b, and 136c send the
liquid back to the heat exchanger.
[0052] FIGS. 1C-1D illustrate reactor body assembly 102 containing
fluid passageways 124a, 124b, 124c, 134a, 134b, and 134c. In one
example, fluid passageway 124a extends within side 120 and along a
partial length of reactor body assembly 102. Fluid passageway 124a
is coupled to and in fluid communication with inlet 122a and outlet
126a. Also, fluid passageway 134a extends within side 130 and along
a partial length of reactor body assembly 102. Fluid passageway
134a is coupled to and in fluid communication with inlet 132a and
outlet 136a.
[0053] In another example, fluid passageway 124b extends within the
shelf or bracket arm 146 within reactor body assembly 102 and along
a partial length of reactor body assembly 102. Fluid passageway
124b is coupled to and in fluid communication with inlet 122b and
outlet 126b. Also, fluid passageway 134b extends within the shelf
or bracket arm 146 within reactor body assembly 102 and along a
partial length of reactor body assembly 102. Fluid passageway 134b
is coupled to and in fluid communication with inlet 132b and outlet
136b.
[0054] In another example, fluid passageway 124c extends from side
120, through the width of reactor body assembly 102, and to side
130. Fluid passageway 124c is coupled to and in fluid communication
with inlet 122c and outlet 132c. Also, fluid passageway 124c
extends from side 130, through the width of reactor body assembly
102, and to side 130. Fluid passageway 124c is coupled to and in
fluid communication with inlet 126c and outlet 136c.
[0055] In another embodiment, reactor body assembly 102 contains
wafer carrier track 400 and heating lamp assembly 600 disposed
therein. Heating lamp system may be used to heat wafer carrier
track 400, wafer carriers, and wafers 90 disposed above and within
reactor 100. Wafer carrier track 400 may be on a shelf, such as
bracket arm 146. Generally, wafer carrier track 400 may be disposed
between bracket arm 146 and clamp arm 148. Bracket arm 146 may
contains fluid passageways 124b and 134b traversing
therethrough.
[0056] In one embodiment, a spacer, such as a gasket or an O-ring
may be disposed between the lower surface of wafer carrier track
400 and the upper surface of bracket arm 146. Also, another spacer,
such as a gasket or an O-ring may be disposed between the upper
surface of wafer carrier track 400 and the lower surface of clamp
arm 148. The spacers may be used to form space or a gap around
wafer carrier track 400, which aids in the thermal management of
wafer carrier track 400. In one example, the upper surface of
bracket arm 146 may have a groove for containing a spacer.
Similarly, the lower surface of clamp arm 148 may have a groove for
containing a spacer.
[0057] FIGS. 2A-2C depict reactor lid assembly 200 according to
another embodiment described herein. Reactor lid assembly 200
contains showerhead assembly 700 and isolator assembly 500 (chamber
station 160) and showerhead assembly 700 and exhaust assembly 800
(chamber station 162) disposed on lid support 210. FIG. 2D depicts
lid support 210 contained within reactor lid assembly 200, as
described in one embodiment. Lid support 210 has lower surface 208
and upper surface 212. Flange 220 extends outwardly from lid
support 210 and has lower surface 222. Flange 220 helps support
reactor lid assembly 200 when disposed on reactor body assembly
102. Lower surface 222 of flange 220 may be in physical contact
with upper surfaces 114, 116, 128, and 138 of reactor body assembly
102.
[0058] In one embodiment, showerhead assemblies 700 may be disposed
within showerhead ports 230 and 250 of lid support 210, isolator
assembly 500 may be disposed within isolator port 240 of lid
support 210, and exhaust assembly 800 may be disposed within
exhaust port 260 of lid support 210. The geometry of the gas or
exhaust assembly generally matches the geometry of the respective
port. Each showerhead assembly 700 and showerhead ports 230 and 250
may independently have a rectangular or square geometry. A process
path--such as the path in which levitating wafer carrier 480
travels forward along wafer carrier track 400 during fabrication
processes--extends along the length of lid support 210 as well as
wafer carrier track 400.
[0059] Showerhead port 230 has length 232 and width 234 and
showerhead port 250 has length 252 and width 254. Isolator assembly
500 and isolator port 240 may independently have a rectangular or
square geometry. Isolator port 240 has length 242 and width 244.
Exhaust assembly 800 and exhaust port 260 may independently have a
rectangular or square geometry. Exhaust port 260 has length 262 and
width 264.
[0060] The process path extends along length 232 of showerhead port
230 and a first showerhead assembly therein, extends along length
242 of isolator port 240 and an isolator assembly therein, extends
along length 252 of showerhead port 250 and a second showerhead
assembly therein, and extends along length 262 of exhaust port 260
and an exhaust assembly therein. Also, the process path extends
perpendicular or substantially perpendicular to width 234 of
showerhead port 230 and a first showerhead assembly therein, to
width 244 of isolator port 240 and an isolator assembly therein, to
width 254 of showerhead port 250 and a second showerhead assembly
therein, and to width 264 of exhaust port 260 and an exhaust
assembly therein.
[0061] In some examples, the first showerhead assembly 700, the
isolator assembly 500, the second showerhead assembly 700, and the
exhaust assembly 800 are consecutively disposed next to each and
along a process path which extends along the length of lid support.
The isolator assembly 500, as well as the exhaust assembly 800 may
each have a width which is substantially the same or greater than
the width of the process path. Also, the isolator assembly 500 or
the exhaust assembly 800 may independently have a width which is
substantially the same or greater than the width of the first and
second showerhead assemblies 700.
[0062] In one embodiment, showerhead assemblies 700 independently
have a square geometry and isolator assembly 500 and exhaust
assembly 800 have a square geometry. In one example, width 244 of
isolator port 240 and the width of isolator assembly 500 may extend
across the width of the interior of the chamber. In another
example, width 264 of exhaust port 260 and the width of exhaust
assembly 800 may extend across the width of the interior of the
chamber.
[0063] In some embodiments, width 234 of showerhead port 230, width
254 of showerhead port 250, and the width of each showerhead
assembly 700 may independently be within a range from about 3 inch
to about 9 inches, preferably, from about 5 inches to about 7
inches, for example, about 6 inches. Also, length 232 of showerhead
port 230, length 252 of showerhead port 250 and the length of each
showerhead assembly 700 may independently be within a range from
about 3 inch to about 9 inches, preferably, from about 5 inches to
about 7 inches, for example, about 6 inches.
[0064] In other embodiments, width 244 of isolator port 240 and the
width of isolator assembly 500 may independently be within a range
from about 3 inches to about 12 inches, preferably, from about 4
inches to about 8 inches, and more preferably, from about 5 inches
to about 6 inches. Also, length 242 of isolator port 240 and the
length of the isolator assembly 500 may independently be within a
range from about 0.5 inches to about 5 inches, preferably, from
about 1 inch to about 4 inches, from about 1.5 inches to about 2
inches.
[0065] In other embodiments, width 264 of exhaust port 260 and the
width of exhaust assembly 800 may independently be within a range
from about 3 inches to about 12 inches, preferably, from about 4
inches to about 8 inches, and more preferably, from about 5 inches
to about 6 inches. Also, length 262 of exhaust port 260 and the
length of the exhaust assembly 800 may independently be within a
range from about 0.5 inches to about 5 inches, preferably, from
about 1 inch to about 4 inches, from about 1.5 inches to about 2
inches.
[0066] Reactor lid assembly 200 may be coupled to and in fluid
communication with at least one heat exchanger as part of the heat
regulation system. In some embodiments, reactor lid assembly 200
may be coupled to and in fluid communication with two, three, or
more heat exchanger.
[0067] The heat regulation system 190 (FIG. 1F) of reactor lid
assembly 200 contains inlets 214a, 216a, and 218a and outlets 214b,
216b, and 218b, as depicted in FIG. 2A. Each pair of the inlet and
outlet is coupled to and in fluid communication with a passageway
extending throughout reactor lid assembly 200. Inlets 214a, 216a,
and 218a may receive a liquid from the heat exchanger while outlets
214b, 216b, and 218b send the liquid back to the heat exchanger,
such as heat exchangers 180a-180c. In some embodiments, the
temperature regulation system 190 utilizes heat exchangers
180a-180c to independently maintain reactor body assembly 102
and/or reactor lid assembly 200 at a temperature within a range
from about 250.degree. C. to about 350.degree. C., preferably, from
about 275.degree. C. to about 325.degree. C., more preferably, from
about 290.degree. C. to about 310.degree. C., such as about
300.degree. C.
[0068] FIGS. 2B-2C illustrate fluid passageways 224, 226, and 228.
Fluid passageway 224 is disposed between inlet 214a and outlet
214b, which may be coupled to and in fluid communication to a heat
exchanger. Fluid passageway 224 is disposed between showerhead
assembly 700 and exhaust assembly 800. Also, fluid passageway 226
is disposed between inlet 216a and outlet 216b, and fluid
passageway 228 is disposed between inlet 218a and outlet 218b,
which both may independently be coupled to and in fluid
communication to a heat exchanger. Fluid passageway 226 is disposed
between showerhead assembly 700 and isolator assembly 500, and
fluid passageway 228 is disposed between showerhead assembly 700
and isolator assembly 500.
[0069] Fluid passageway 224 is partially formed between groove 213
and plate 223. Similarly, fluid passageway 226 is partially formed
between groove 215 and plate 225, and fluid passageway 228 is
partially formed between groove 217 and plate 227. Grooves 213,
215, and 217 may be formed within lower surface 208 of lid support
210. FIG. 2D depicts plates 223, 225, and 227 respectively covering
grooves 213, 215, and 217.
[0070] In one embodiment, a reactor lid assembly 200 for vapor
deposition is provided which includes a first showerhead assembly
700 and an isolator assembly 500 disposed next to each other on a
lid support 210, and a second showerhead assembly 700 and an
exhaust assembly 800 disposed next to each other on the lid support
210, wherein the isolator assembly 500 is disposed between the
first and second showerhead assemblies 700 and the second
showerhead assembly 700 is disposed between the isolator assembly
500 and the exhaust assembly 800.
[0071] In another embodiment, a reactor lid assembly 200 for vapor
deposition is provided which includes a chamber station 160 having
a first showerhead assembly 700 and an isolator assembly 500
disposed next to each other on a lid support 210, and a chamber
station 162 having a second showerhead assembly 700 and an exhaust
assembly 800 disposed next to each other on the lid support 210,
wherein the isolator assembly 500 is disposed between the first and
second showerhead assemblies 700 and the second showerhead assembly
700 is disposed between the isolator assembly 500 and the exhaust
assembly 800.
[0072] In another embodiment, a reactor lid assembly 200 for vapor
deposition is provided which includes a first showerhead assembly
700, an isolator assembly 500, a second showerhead assembly 700,
and an exhaust assembly 800 consecutively and linearly disposed
next to each other on a lid support 210, wherein the isolator
assembly 500 is disposed between the first and second showerhead
assemblies 700 and the second showerhead assembly 700 is disposed
between the isolator assembly 500 and the exhaust assembly 800.
[0073] In another embodiment, a reactor lid assembly 200 for vapor
deposition is provided which includes a first showerhead assembly
700, an isolator assembly 500, a second showerhead assembly 700,
and an exhaust assembly 800 consecutively and linearly disposed
next to each other on a lid support 210, and a temperature
regulation system 190 having at least one liquid or fluid
passageway, but often may have two, three, or more liquid or fluid
passageways, such as fluid passageways 224, 226, and 228, extending
throughout the lid support 210. The temperature regulation system
190 further has at least one inlet, such as inlets 214a, 216a, and
218a, and at least one outlet, such as outlets 214b, 216b, and
218b, coupled to and in fluid communication with the fluid
passageways 224, 226, and 228. Each of the inlets 214a, 216a, and
218a and outlets 214b, 216b, and 218b may be independently coupled
to and in fluid communication with a liquid reservoir, a heat
exchanger, or multiple heat exchangers, such as heat exchangers
180a, 180b, and 180c. In one example, the liquid reservoir may
contain or be a source of water, alcohols, glycols, glycol ethers,
organic solvents, or mixtures thereof.
[0074] In one example, the first showerhead assembly 700 may be
disposed between the two independent fluid passageways of the
temperature regulation system 190 which extend through the reactor
lid assembly 200. In another example, the second showerhead
assembly 700 may be disposed between the two independent fluid
passageways of the temperature regulation system 190 which extend
through the reactor lid assembly 200. In another example, the
isolator assembly 500 may be disposed between the two independent
fluid passageways of the temperature regulation system 190 which
extend through the reactor lid assembly 200. In another example,
the exhaust assembly 800 may be disposed between the two
independent fluid passageways of the temperature regulation system
190 which extend through the reactor lid assembly 200.
[0075] In another embodiment, a reactor lid assembly 200 for vapor
deposition is provided which includes a chamber station 160 having
a first showerhead assembly 700 and an isolator assembly 500
disposed next to each other on a lid support 210, a chamber station
162 having a second showerhead assembly 700 and an exhaust assembly
800 disposed next to each other on the lid support 210, wherein the
isolator assembly 500 is disposed between the first and second
showerhead assemblies 700, and the temperature regulation system
190.
[0076] In one embodiment, the first showerhead assembly 700, the
isolator assembly 500, the second showerhead assembly 700, and the
exhaust assembly 800 are consecutively disposed next to each and
along the length of lid support 210. In some embodiments, the
isolator assembly 500 may have a longer width than the first or
second showerhead assembly 700. In other embodiments, the isolator
assembly 500 may have a shorter length than the first or second
showerhead assembly 700. In some embodiments, the exhaust assembly
800 may have a longer width than the first or second showerhead
assembly 700. In other embodiments, the exhaust assembly 800 may
have a shorter length than the first or second showerhead assembly
700.
[0077] In some examples, the first showerhead assembly 700, the
isolator assembly 500, the second showerhead assembly 700, and the
exhaust assembly 800 independently have a rectangular geometry. In
other examples, the first showerhead assembly 700 and the second
showerhead assembly 700 have a square geometry. The lid support 210
may contain or be made from a material such as steel, stainless
steel, 300 series stainless steel, iron, nickel, chromium,
molybdenum, aluminum, alloys thereof, or combinations thereof.
[0078] Embodiments provide that each of the isolator assembly 500
or the first or second showerhead assemblies 700 independently has
a body 502 or 702 containing upper portion 506 or 706 disposed on a
lower portion 504 or 704, a centralized channel 516 or 716
extending through the upper portion 506 or 706 and the lower
portion 504 or 704, between inner surfaces 509 or 709 of the body
502 or 702, and parallel to a central axis 501 or 701 extending
through the body 502 or 702 and an optional diffusion plate 530 or
730 having a first plurality of holes 532 or 732 and disposed
within the centralized channel 516 or 716. The isolator assembly
500 or the first or second showerhead assemblies 700 independently
have an upper tube plate 540 or 740 having a second plurality of
holes 542 or 742 and disposed within the centralized channel 516 or
716 and optionally below the diffusion plate 530 or 730 and a lower
tube plate 550 or 750 having a third plurality of holes 552 or 752
and disposed within the centralized channel 516 or 716 below the
upper tube plate 540 or 740. Either of the showerhead assemblies
700 or the isolator assembly 500 independently may further have a
plurality of gas tubes 580 or 780 extending from the upper tube
plate 540 or 740 to the lower tube plate 550 or 750, wherein each
of the gas tubes 580 or 780 is coupled to and in fluid
communication with an individual hole from the second plurality of
holes 542 or 742 and an individual hole from the third plurality of
holes 552 or 752.
[0079] In another embodiment, an exhaust assembly 800 contains a
body 802 having an upper portion 806 disposed on a lower portion
804, a centralized channel 816 extending through the upper portion
806 and the lower portion 804, between inner surfaces 809 of the
body 802, and parallel to a central axis 801 extending through the
body 802, an exhaust outlet 860 disposed on the upper portion 806
of the body 802, an optional diffusion plate 830 having a first
plurality of holes 832 and disposed within the centralized channel
816, an upper tube plate 840 having a second plurality of holes 842
and disposed within the centralized channel 816 and optionally
below the diffusion plate 830 (if present), a lower tube plate 850
having a third plurality of holes 852 and disposed within the
centralized channel 816 below the upper tube plate 840. The exhaust
assembly 800 may further contain a plurality of exhaust tubes 880
extending from the upper tube plate 840 to the lower tube plate
850, wherein each of the exhaust tubes 880 is coupled to and in
fluid communication with an individual hole from the second
plurality of holes 842 and an individual hole from the third
plurality of holes 852.
[0080] FIGS. 4A-4E depict wafer carrier track 400 according to one
embodiment described herein. In another embodiment, wafer carrier
track 400 for levitating and traversing a substrate susceptor, such
as levitating wafer carrier 480 within a vapor deposition reactor
system, such as reactor 100, is provided which includes an upper
segment 410 of wafer carrier track 400 disposed over a lower
segment 412 of wafer carrier track 400. Gas cavity 430 is formed
between upper segment 410 and lower segment 412 of wafer carrier
track 400. Two side surfaces 416 extend along upper segment 410 of
wafer carrier track 400 and parallel to each other. Guide path 420
extends between the two side surfaces 416 and along upper surface
418 of upper segment 410. A plurality of gas holes 438 is disposed
within guide path 420 and extend from upper surface 418 of upper
segment 410, through upper segment 410, and into gas cavity
430.
[0081] In another embodiment, upper lap joint 440 is disposed at
one end of wafer carrier track 400 and lower lap joint 450 is
disposed at the opposite end of wafer carrier track 400, wherein
upper lap joint 440 extends along a portion of guide path 420 and
side surfaces 416. Upper lap joint 440 has lower surface 442
extending further than lower segment 412. Lower lap joint 450 has
upper surface 452 extending further than guide path 420 and side
surfaces 416 of wafer carrier track 400.
[0082] Generally, upper segment 410 and/or lower segment 412 of
wafer carrier track 400 may independently contain quartz. In some
examples, lower segment 412 of wafer carrier track 400 may be a
quartz plate. Upper segment 410 and lower segment 412 of wafer
carrier track 400 may be fused together. In one specific example,
upper segment 410 and lower segment 412 both contain quartz and are
fused together forming gas cavity therebetween. The quartz
contained in upper segment 410 and/or lower segment 412 of wafer
carrier track 400 is usually transparent, but in some embodiments,
portions of wafer carrier track 400 may contain quartz that is
opaque.
[0083] In another embodiment, gas port 434 extends from side
surface 402 of wafer carrier track 400 and into gas cavity 430. In
one example, gas port 434 extends through upper segment 410. The
plurality of gas holes 438 may number from about 10 holes to about
50 holes, preferably, from about 20 holes to about 40 holes. Each
of the gas holes 438 may have a diameter within a range from about
0.005 inches to about 0.05 inches, preferably, from about 0.01
inches to about 0.03 inches.
[0084] In other embodiments, a wafer carrier track system may
contain two or more wafer carrier tracks 400 disposed end to end in
series, as depicted in FIGS. 4D-4E. In one embodiment, the wafer
carrier track system is provided which includes an upper lap joint
440 of a first wafer carrier track 400 disposed over a lower lap
joint 450 of a second wafer carrier track 400, an exhaust port
formed between the upper lap joint 440 of the first wafer carrier
track 400 and the lower lap joint 450 of the second wafer carrier
track 400, and a first guide path on an upper surface of the first
wafer carrier track 400 aligned with a second guide path on an
upper surface of the second wafer carrier track 400. In some
examples, an upper lap joint 440 of the second wafer carrier track
400 may be disposed over a lower lap joint 450 of a third wafer
carrier track 400 (not shown).
[0085] In another embodiment, wafer carrier track 400 for
levitating and traversing levitating wafer carrier 480 within a
vapor deposition reactor system, such as reactor 100, is provided
which includes wafer carrier track 400 having gas cavity 430 formed
within, guide path 420 extending along an upper surface of wafer
carrier track 400, a plurality of gas holes 438 within guide path
420 and extending from the upper surface of wafer carrier track 400
and into gas cavity 430, and an upper lap joint 440 disposed at one
end of wafer carrier track 400 and a lower lap joint 450 disposed
at the opposite end of wafer carrier track 400, wherein the upper
lap joint 440 extends a portion of guide path 420 and the lower lap
joint 450 has an upper surface extending further than guide path
420 of wafer carrier track 400.
[0086] At least one side surface may be disposed on wafer carrier
track 400 and extends along and above guide path 420. In some
examples, two side surfaces 416 are disposed on wafer carrier track
400 and extend along and above guide path 420. Guide path 420 may
extend between the two side surfaces 416. In one embodiment, an
upper segment 410 of wafer carrier track 400 may be disposed over a
lower segment 412 of wafer carrier track 400. Upper segment 410 of
wafer carrier track 400 may have guide path 420 extending along the
upper surface. Gas cavity 430 may be formed between upper segment
410 and lower segment 412 of wafer carrier track 400. In some
examples, upper segment 410 and lower segment 412 of wafer carrier
track 400 may be fused together. In some embodiments, wafer carrier
track 400 contains quartz. Upper segment 410 and lower segment 412
of wafer carrier track 400 may independently contain quartz. In one
example, lower segment 412 of wafer carrier track 400 is a quartz
plate.
[0087] In other embodiments, gas port 434 extends from a side
surface of wafer carrier track 400 and into gas cavity 430. Gas
port 434 may be utilized to flow the levitating gas through the
side surface of wafer carrier track 400, into gas cavity 430 and
out from the plurality of gas holes 438 on the upper surface of
wafer carrier track 400. The plurality of gas holes 438 may number
from about 10 holes to about 50 holes, preferably, from about 20
holes to about 40 holes. Each gas hole 438 may have a diameter
within a range from about 0.005 inches to about 0.05 inches,
preferably, from about 0.01 inches to about 0.03 inches.
[0088] In another embodiment, FIGS. 12A-12E depict levitating wafer
carrier 480 which may be used to carry a substrate through a
variety of processing chambers including the CVD reactors as
described herein, as well as other processing chambers used for
deposition or etching. Levitating wafer carrier 480 has short sides
471, long sides 473, an upper surface 472, and a lower surface 474.
Levitating wafer carrier 480 is illustrated with a rectangular
geometry, but may also have a square geometry, a circular geometry,
or other geometries. Levitating wafer carrier 480 may contain or be
formed from graphite or other materials. Levitating wafer carrier
480 usually travels through the CVD reactor with the short sides
471 facing forward while the long sides 473 face towards the sides
of the CVD reactor.
[0089] FIGS. 12A-12B depict levitating wafer carrier 480 according
to one embodiment described herein. FIG. 12A illustrates a top view
of levitating wafer carrier 480 containing 3 indentations 475 on
the upper surface 472. Wafers or substrates may be positioned
within the indentations 475 while being transferred through the CVD
reactor during a process. Although illustrated with 3 indentations
475, the upper surface 472 may have more or less indentations,
including no indentations. For example, the upper surface 472 of
levitating wafer carrier 480 may contain 0, 1, 2, 3, 4, 5, 6, 7, 8,
9, 10, 12, or more indentations for containing wafers or
substrates. In some example, one wafer/substrate or multiple
wafers/substrates may be disposed directly on the upper surface 472
which does not have an indentation.
[0090] FIG. 12B illustrates a bottom view of levitating wafer
carrier 480 containing the indentation 478 on the lower surface
474, as described in one embodiment herein. The indentation 478 may
be used to help levitate levitating wafer carrier 480 upon the
introduction of a gas cushion under levitating wafer carrier 480. A
gas flow may be directed at the indentation 478, which accumulates
gas to form the gas cushion. The lower surface 474 of levitating
wafer carrier 480 may have no indentations, or may have one
indentation 478 (FIG. 12B), two indentations 478 (FIGS. 12C-12E),
three indentations 478 (not shown) or more. Each of the
indentations 478 may have straight or tapered sides. In one
example, each indentation 478 has tapered sides such that the sides
476 are steeper or more abrupt than the sides 477 which have more
of a gradual change of angle. The sides 477 within the indentation
478 may be tapered to compensate for a thermal gradient across
levitating wafer carrier 480. Also, the sides 477 may be tapered or
angled to help form a gas pocket and to maintain the gas pocket
under levitating wafer carrier 480 while lifting and
moving/traversing levitating wafer carrier 480 along wafer carrier
track 400. In another example, the indentation 478 has straight or
substantially straight sides and tapered sides such that the sides
476 are straight or substantially straight and the sides 477 have a
taper/angle or the sides 477 are straight or substantially straight
and the sides 476 have a taper/angle. Alternatively, the
indentation 478 may have all straight sides such that the sides 476
and 477 are straight or substantially straight.
[0091] In another embodiment, FIGS. 12C-12E illustrate bottom views
of levitating wafer carrier 480 containing two indentations 478 on
the lower surface 474. The two indentations 478 help levitate
levitating wafer carrier 480 upon the introduction of a gas cushion
under levitating wafer carrier 480. A gas flow may be directed at
the indentations 478, which accumulates gas to form the gas
cushion. The indentations 478 may have straight or tapered sides.
In one example, as illustrated in FIG. 10E, the indentations 478
have all straight sides such that the sides 476 and 477 are
straight, e.g., perpendicular to the plane of the lower surface
474. In another example, as illustrated in FIG. 10F, the
indentations 478 have all tapered sides such that the sides 476 are
steeper or more abrupt than the sides 477 which have more of a
gradual change of angle. The sides 477 within the indentations 478
may be tapered to compensate for a thermal gradient across
levitating wafer carrier 480. Alternatively, the indentations 478
may have a combination of straight sides and tapered sides such
that the sides 476 are straight and the sides 477 have a taper or
the sides 477 are straight and the sides 476 have a taper.
[0092] Levitating wafer carrier 480 contains a heat flux which
extends from the lower surface 474 to the upper surface 472 and to
any substrates disposed thereon. The heat flux may be controlled by
both the internal pressure and length of the processing system. The
profile of levitating wafer carrier 480 may be tapered to
compensate the heat loses from other sources. During a process,
heat is lost through the edges of levitating wafer carrier 480,
such as the short sides 471 and the long sides 473. However, the
heat lost may be compensated by allowing more heat flux into the
edges of levitating wafer carrier 480 by reducing the gap of the
channel in the levitation.
[0093] In another embodiment, wafer carrier track 400 contains
levitating wafer carrier 480 disposed on guide path 420. In some
examples, levitating wafer carrier 480 has at least one indentation
pocket disposed within a lower surface. In other examples,
levitating wafer carrier 480 has at least two indentation pockets
disposed within a lower surface.
[0094] FIGS. 5A-5D depict isolator assembly 500 for a vapor
deposition chamber, such as reactor 100, according embodiments
described herein. In one embodiment, isolator assembly 500 includes
body 502 having upper portion 506 and lower portion 504, and
centralized channel 516 extending through upper portion 506 and
lower portion 504 of body 502. Upper portion 506 contains upper
surface 507. Centralized channel 516 extends between inner surfaces
509 of body 502, and parallel to central axis 501 extending through
body 502. Diffusion plate 530 contains a plurality of gas holes 532
and is disposed within centralized channel 516. In one example,
diffusion plate 530 is disposed on a flange or ledge 510. In
another example, isolator assembly 500 does not contain diffusion
plate 530 disposed therein.
[0095] Isolator assembly 500 further contains upper tube plate 540
having a plurality of gas holes 542 and disposed within centralized
channel 516 below diffusion plate 530. Isolator assembly 500 also
contains lower tube plate 550 having a plurality of gas holes 552
and disposed within centralized channel 516 below upper tube plate
540. A plurality of gas tubes 580 extend from upper tube plate 540
to lower tube plate 550, wherein each tube is coupled to and in
fluid communication with an individual hole from the plurality of
gas holes 542 and an individual hole from plurality of gas holes
552. Each of the gas tubes 580 extends parallel or substantially
parallel to each other as well as to central axis 501 in many
embodiments described herein. In an alternative embodiment, not
shown, each of the gas tubes 580 may extend at a predetermined
angle relative to central axis 501, such as within a range from
about 1.degree. to about 15.degree. or greater.
[0096] Isolator assembly 500 may be used to disperse gases, such as
purge gases, precursor gases, and/or carrier gases, by providing a
flow path through inlet port 522 and into cavities 538, 548, and
558. Cavity 538 is formed between upper plate 520 and diffusion
plate 530 within centralized channel 516. Cavity 548 is formed
between diffusion plate 530 and upper tube plate 540 within
centralized channel 516. Cavity 558 is formed between upper tube
plate 540 and lower tube plate 550 within centralized channel
516.
[0097] In another embodiment, isolator assembly 500 includes body
502 containing upper portion 506 and lower portion 504, wherein
upper portion 506 contains a flange extending over lower portion
504, centralized channel 516 extending through upper portion 506
and lower portion 504 of body 502, between inner surfaces 509 of
body 502, and parallel to central axis 501 extending through body
502, diffusion plate 530 containing a plurality of gas holes 532
and disposed within centralized channel 516, upper tube plate 540
containing a plurality of gas holes 542 and disposed within
centralized channel 516 below diffusion plate 530, lower tube plate
550 containing a plurality of gas holes 552 and disposed within
centralized channel 516 below upper tube plate 540, and plurality
of gas tubes 580 extending from upper tube plate 540 to lower tube
plate 550, wherein each tube is coupled to and in fluid
communication with an individual hole from plurality of gas holes
542 and an individual hole from plurality of gas holes 552.
[0098] In another embodiment, isolator assembly 500 includes body
502 containing upper portion 506 and lower portion 504, wherein
upper portion 506 adjacently extends from central axis 501 of body
502 further than lower portion 504 and lower portion 504 extends
parallel to central axis 501 further than upper portion 506,
centralized channel 516 extending through upper portion 506 and
lower portion 504 of body 502, between inner surfaces 509 of body
502, and parallel to central axis 501, diffusion plate 530
containing a plurality of gas holes 532 and disposed within
centralized channel 516, upper tube plate 540 containing a
plurality of gas holes 542 and disposed within centralized channel
516 below diffusion plate 530, lower tube plate 550 containing a
plurality of gas holes 552 and disposed within centralized channel
516 below upper tube plate 540, and plurality of gas tubes 580
extending from upper tube plate 540 to lower tube plate 550,
wherein each tube is coupled to and in fluid communication with an
individual hole from plurality of gas holes 542 and an individual
hole from plurality of gas holes 552.
[0099] In another embodiment, isolator assembly 500 includes body
502 containing upper portion 506 and lower portion 504, centralized
channel 516 extending through upper portion 506 and lower portion
504 of body 502, between inner surfaces 509 of body 502, and
parallel to central axis 501 extending through body 502, diffusion
plate 530 containing a plurality of gas holes 532 and disposed
within centralized channel 516, upper tube plate 540 containing a
plurality of gas holes 542 and disposed within centralized channel
516 below diffusion plate 530, and lower tube plate 550 containing
a plurality of gas holes 552 and disposed within centralized
channel 516 below upper tube plate 540.
[0100] In another embodiment, isolator assembly 500 includes body
502 containing upper portion 506 and lower portion 504, centralized
channel 516 extending through upper portion 506 and lower portion
504 of body 502, between inner surfaces 509 of body 502, and
parallel to central axis 501 extending through body 502, upper tube
plate 540 containing a plurality of gas holes 532 and disposed
within centralized channel 516 below diffusion plate 530, lower
tube plate 550 containing a plurality of gas holes 542 and disposed
within centralized channel 516 below upper tube plate 540, and
plurality of gas tubes 580 extending from upper tube plate 540 to
lower tube plate 550, wherein each tube is coupled to and in fluid
communication with an individual hole from plurality of gas holes
532 and an individual hole from plurality of gas holes 542.
[0101] In some embodiments, isolator assembly 500 is a modular
showerhead assembly. Upper portion 506 and lower portion 504 of
body 502 may independently contain a material such as steel,
stainless steel, 300 series stainless steel, iron, nickel,
chromium, molybdenum, aluminum, alloys thereof, or combinations
thereof. In one example, upper portion 506 and lower portion 504 of
body 502 each independently contains stainless steel or alloys
thereof.
[0102] In one embodiment, isolator assembly 500 contains gaseous
inlet 560 disposed on upper portion 506 of body 502. Upper plate
520 may be disposed on an upper surface of upper portion 506 of
body 502 and gaseous inlet 560 may be disposed on the plate. The
plate may contain a material such as steel, stainless steel, 300
series stainless steel, iron, nickel, chromium, molybdenum,
aluminum, alloys thereof, or combinations thereof. In some
examples, the plate has inlet port 522 extending therethrough.
Gaseous inlet 560 has inlet tube 564 extending through inlet port
522. Inlet nozzle 562 may be coupled to one end of inlet tube 564
and disposed above the plate. In another example, the upper surface
of upper portion 506 of the showerhead body has groove 508 which
encompasses centralized channel 516. An O-ring may be disposed
within groove 508. Diffusion plate 530 may be disposed on a ledge
or a flange protruding from side surfaces of body 502 within
centralized channel 516.
[0103] In one embodiment, plurality of gas tubes 580 may have tubes
numbering within a range from about 500 tubes to about 1,500 tubes,
preferably, from about 700 tubes to about 1,200 tubes, and more
preferably, from about 800 tubes to about 1,000 tubes, for example,
about 900 tubes. In some examples, each tube may have a length
within a range from about 0.5 cm to about 2 cm, preferably, from
about 0.8 cm to about 1.2 cm, for example, about 1 cm. In other
examples, each tube may have a diameter within a range from about
0.005 inches to about 0.05 inches, preferably, from about 0.01
inches to about 0.03 inches. In some examples, the tubes are
hypodermic needles. The tubes may contain or be made from a
material such as steel, stainless steel, 300 series stainless
steel, iron, nickel, chromium, molybdenum, aluminum, alloys
thereof, or combinations thereof.
[0104] In one embodiment, each hole of plurality of gas holes 532
on diffusion plate 530 has a larger diameter than each hole of
plurality of gas holes 542 on upper tube plate 540. Further, each
hole of plurality of gas holes 532 on diffusion plate 530 has a
larger diameter than each hole of plurality of gas holes 552 on the
lower diffusion plate. Also, each hole of plurality of gas holes
542 on upper tube plate 540 has the same diameter or substantially
the same diameter as each hole of plurality of gas holes 552 on
lower tube plate 550.
[0105] In one embodiment, diffusion plate 530 may contain or be
made from a material such as steel, stainless steel, 300 series
stainless steel, iron, nickel, chromium, molybdenum, aluminum,
alloys thereof, or combinations thereof. Diffusion plate 530 may
contain holes numbering within a range from about 20 holes to about
200 holes, preferably, from about 25 holes to about 55 holes, and
more preferably, from about 40 holes to about 60 holes. Each hole
of diffusion plate 530 may have a diameter within a range from
about 0.005 inches to about 0.05 inches, preferably, from about
0.01 inches to about 0.03 inches. In another embodiment, upper tube
plate 540 and/or lower tube plate 550 may independently contain or
be independently made from a material such as steel, stainless
steel, 300 series stainless steel, iron, nickel, chromium,
molybdenum, aluminum, alloys thereof, or combinations thereof.
Upper tube plate 540 and/or lower tube plate 550 may independently
have from about 500 holes to about 1,500 holes, preferably, from
about 700 holes to about 1,200 holes, and more preferably, from
about 800 holes to about 1,000 holes. Each hole of upper tube plate
540 and/or lower tube plate 550 may independently have a diameter
within a range from about 0.005 inches to about 0.05 inches,
preferably, from about 0.01 inches to about 0.03 inches. In another
embodiment, isolator assembly 500 may have a gaseous hole density
and/or number of tubes within a range from about 10 holes/in.sup.2
(holes per square inch) to about 60 holes/in.sup.2, preferably,
from about 15 holes/in.sup.2 to about 45 holes/in.sup.2, and more
preferably, from about 20 holes/in.sup.2 to about 36
holes/in.sup.2.
[0106] In one example, the upper surface of upper portion 506 of
body 502 of isolator assembly 500 is a metallic plate. In other
examples, isolator assembly 500 may have a rectangular geometry or
a square geometry. In another embodiment, body 502 of isolator
assembly 500 further contains a temperature regulation system. The
temperature regulation system, such as temperature regulation
system 190, may contain fluid passageway 518 extending within body
502, and may have inlet 514a and outlet 514b coupled to and in
fluid communication with fluid passageway 518. Inlet 514a and
outlet 514b may be independently coupled to and in fluid
communication with a liquid reservoir or at least one heat
exchanger, such as heat exchangers 180a, 180b, or 180c within
temperature regulation system 190, as depicted in FIG. 1F.
[0107] FIG. 6 depicts heating lamp assembly 600, which may be
utilized to heat wafers or substrates, as well as wafer carriers or
substrate supports within a vapor deposition reactor system, as
described in embodiments herein. In one embodiment, heating lamp
assembly 600 is provided which includes lamp housing 610 disposed
on upper surface 606 of support base 602 and containing first lamp
holder 620a and second lamp holder 620b, a plurality of lamps 624
extending from first lamp holder 620a to second lamp holder 620b,
wherein each lamp 624 has a split filament or a non-split filament,
and reflector 650 disposed on upper surface 606 of support base 602
is disposed between first lamp holder 620a and second lamp holder
620b.
[0108] In another embodiment, heating lamp assembly 600 includes
lamp housing 610 disposed on upper surface 606 of support base 602
and containing first lamp holder 620a and second lamp holder 620b,
a first plurality of lamps 624 extending from first lamp holder
620a to second lamp holder 620b, wherein each lamp of the first
plurality has a split filament, a second plurality of lamps 624
extending from first lamp holder 620a to second lamp holder 620b,
wherein each lamp of the second plurality has a non-split filament,
and reflector 650 disposed on upper surface 606 of support base 602
between first lamp holder 620a and second lamp holder 620b.
[0109] In another embodiment, heating lamp assembly 600 includes
lamp housing 610 disposed on upper surface 606 of support base 602
and containing first lamp holder 620a and second lamp holder 620b,
a first plurality of lamps 624 extending from first lamp holder
620a to second lamp holder 620b, wherein each lamp of the first
plurality has a split filament, a second plurality of lamps 624
extending from first lamp holder 620a to second lamp holder 620b,
wherein each lamp of the second plurality has a non-split filament,
and the first plurality of lamps 624 are sequentially or
alternately disposed between the second plurality of lamps 624
while extending between the first and second lamp holders. Also,
reflector 650 may be disposed on upper surface 606 of support base
602 between first lamp holder 620a and second lamp holder 620b.
[0110] In another embodiment, heating lamp assembly 600 includes
lamp housing 610 disposed on upper surface 606 of support base 602
and containing first lamp holder 620a and second lamp holder 620b,
a plurality of lamps 624 extending from first lamp holder 620a to
second lamp holder 620b, wherein the plurality of lamps 624 contain
a first group of lamps and a second group of lamps sequentially or
alternately disposed between each other, each lamp of the first
group of lamps contains a split filament, and each lamp of the
second group of lamps contains a non-split filament, and reflector
650 disposed on upper surface 606 of support base 602 between first
lamp holder 620a and second lamp holder 620b.
[0111] In another embodiment, heating lamp assembly 600 includes
lamp housing 610 disposed on upper surface 606 of support base 602
and containing first lamp holder 620a and second lamp holder 620b,
a plurality of posts 622 disposed on first lamp holder 620a and
second lamp holder 620b, a plurality of lamps 624 extending from
first lamp holder 620a to second lamp holder 620b, wherein each
lamp has a split filament or a non-split filament, and reflector
650 disposed on upper surface 606 of support base 602 between first
lamp holder 620a and second lamp holder 620b.
[0112] In another embodiment, heating lamp assembly 600 includes
lamp housing 610 disposed on upper surface 606 of support base 602
and containing first lamp holder 620a and second lamp holder 620b,
a plurality of posts 622 disposed on first lamp holder 620a and
second lamp holder 620b, a plurality of lamps 624 extending from
first lamp holder 620a to second lamp holder 620b, wherein each
lamp has a split filament or a non-split filament, and each lamp
has a first end disposed between two posts 622 on first lamp holder
620a and a second end disposed between two posts 622 on second lamp
holder 620b, and reflector 650 disposed on upper surface 606 of
support base 602 between first lamp holder 620a and second lamp
holder 620b.
[0113] In another embodiment, heating lamp assembly 600 includes
lamp housing 610 disposed on upper surface 606 of support base 602
and containing first lamp holder 620a and second lamp holder 620b,
a plurality of posts 622 disposed on first lamp holder 620a and
second lamp holder 620b, a plurality of lamps 624 extending from
first lamp holder 620a to second lamp holder 620b, wherein each
lamp has a first end disposed between two posts 622 on first lamp
holder 620a and a second end disposed between two posts 622 on
second lamp holder 620b, and reflector 650 disposed on upper
surface 606 of support base 602 between first lamp holder 620a and
second lamp holder 620b.
[0114] In another embodiment, heating lamp assembly 600 includes
lamp housing 610 disposed on upper surface 606 of support base 602
and containing first lamp holder 620a and second lamp holder 620b,
a plurality of posts 622 disposed on first lamp holder 620a and
second lamp holder 620b, a plurality of lamps 624 extending from
first lamp holder 620a to second lamp holder 620b, and reflector
650 disposed on upper surface 606 of support base 602 between first
lamp holder 620a and second lamp holder 620b.
[0115] In another embodiment, heating lamp assembly 600 for a vapor
deposition reactor system is provided which includes lamp housing
610 disposed on upper surface 606 of support base 602 and
containing first lamp holder 620a and second lamp holder 620b, a
plurality of lamps 624 extending from first lamp holder 620a to
second lamp holder 620b, and reflector 650 disposed on upper
surface 606 of support base 602 between first lamp holder 620a and
second lamp holder 620b.
[0116] In one embodiment, heating lamp assembly 600 contains
reflector 650 and/or the upper surface of reflector 650 contains a
reflective metal, such as gold, silver, copper, aluminum, nickel,
chromium, alloys thereof, or combinations thereof. In many
examples, reflector 650 and/or the upper surface of reflector 650
contains gold or a gold alloy. The lower surface of wafer carrier
track 400 may be exposed to radiation emitted from lamps 624 within
heating lamp assembly 600 and reflected from reflector 650, the
upper surface of reflector 650, and/or each mirror 652. The emitted
radiation is absorbed by wafer carrier track 400, levitating wafer
carrier 460, and wafers 90 within reactor 100. In some embodiments
of processes described herein, wafer carrier track 400, levitating
wafer carrier 460, and/or wafers 90 may each be independently
heated by the emitted radiation to a temperature within a range
from about 250.degree. C. to about 350.degree. C., preferably, from
about 275.degree. C. to about 325.degree. C., preferably, from
about 290.degree. C. to about 310.degree. C., such as about
300.degree. C.
[0117] Heating lamp assembly 600 may contain at least one mirror
652 which extends along upper surface 606 of support base 602 and
may be perpendicular or substantially perpendicular to upper
surface 606 of support base 602. In some examples, mirror 652 may
be the inner side surfaces of each lamp holder 620a or 620b having
a reflective coating deposited or otherwise disposed thereon. In
other examples, mirror 652 may be a prefabricated or modular mirror
or reflective material which is attached or adhered to the inner
side surfaces of each lamp holder 620a or 620b. The at least one
mirror 652 is generally positioned to face towards reflector 650 at
an angle of about 90.degree. relative to the plane of surface 606.
Preferably, in another embodiment described herein, heating lamp
assembly 600 contains two mirrors 652 extending along upper surface
606 of support base 602. Both mirrors may be perpendicular or
substantially perpendicular to upper surface 606 of support base
602 and both mirrors 652 may face towards each other with reflector
650 therebetween. Each of the two mirrors 652 faces towards
reflector 650 at an angle of about 90.degree. relative to the plane
of surface 606. Each mirror and/or the upper surface of each mirror
652 contains a reflective metal, such as gold, silver, copper,
aluminum, nickel, chromium, alloys thereof, or combinations
thereof. In many examples, each mirror 652 and/or the upper surface
of each mirror 652 contains gold or a gold alloy.
[0118] In alternative embodiments, not shown, each mirror 652 may
be positioned to slightly face away from reflector 650 at an angle
of greater than 90.degree. relative to the plane of surface 606,
such at an angle within a range from greater than 90.degree. to
about 135.degree.. Mirror 652 positioned at an angle of greater
than 90.degree. may be utilized to direct energy towards wafer
carrier track 400, levitating wafer carrier 460, or other parts or
surfaces within reactor 100. In alternative embodiments, heating
lamp assembly 600 may contain three or more mirrors 652 along upper
surface 606 of support base 602.
[0119] The plurality of lamps 624 within heating lamp assembly 600
may number from about 10 lamps to about 100 lamps, preferably, from
about 20 lamps to about 50 lamps, and more preferably, from about
30 lamps to about 40 lamps. In one example, heating lamp assembly
600 contains about 34 lamps. Embodiments provide that each lamp may
be in electrical contact with a power source, an independent
switch, and a controller. The controller may be used to
independently control power to each lamp.
[0120] In other embodiments, support base 602 and each lamp holder
620a or 620b within heating lamp assembly 600 may independently
contain or be made from a material such as steel, stainless steel,
300 series stainless steel, iron, nickel, chromium, molybdenum,
aluminum, alloys thereof, or combinations thereof. In some
examples, first lamp holder 620a or second lamp holder 620b may
independently contain or be made from stainless steel or alloys
thereof. First lamp holder 620a or second lamp holder 620b
independently may have a cooling coefficient within a range from
about 2,000 W/m.sup.2-K to about 3,000 W/m.sup.2-K, preferably,
from about 2,300 W/m.sup.2-K to about 2,700 W/m.sup.2-K. In one
example, the cooling coefficient is about 2,500 W/m.sup.2-K. In
other embodiments, first lamp holder 620a and second lamp holder
620b each have a thickness within a range from about 0.001 inches
to about 0.1 inches.
[0121] FIG. 10A depicts a non-split filament lamp 670 and FIG. 10B
depicts a split filament lamp 680 according to multiple embodiments
described herein. Non-split filament lamp 670 contains bulb 672 and
non-split filament 674, while split filament lamp 680 contains bulb
682 and non-split filament 684. The plurality of lamps 624, as
described throughout embodiments herein, generally contain
non-split filament lamps 670, split filament lamps 680, or mixtures
of non-split filament lamps 670 and split filament lamps 680.
[0122] FIGS. 11A-11F depict different pluralities of lamps which
may be lamps 624 and utilized to adjust a heat profile on a wafer
carrier track, such as wafer carrier track 400, a wafer carrier or
substrate support, such as levitating wafer carrier 480, and/or a
wafer or a substrate, such as wafers 90, within a vapor deposition
reactor, such as reactor 100, as described in embodiments herein.
In one embodiment, FIG. 11A illustrates a plurality of lamps
containing all non-split filament lamps 670 and FIG. 11B
illustrates a plurality of lamps containing all split filament
lamps 680. In another embodiment, FIG. 11C illustrates a plurality
of lamps sequentially or alternatively containing non-split
filament lamps 670 and split filament lamps 680. In other
embodiments, FIG. 11D illustrates a plurality of lamps containing a
split filament lamp 680 between every two non-split filament lamps
670, while FIG. 11E illustrates a plurality of lamps containing a
non-split filament lamp 670 between every two split filament lamps
680. FIG. 11F illustrates a plurality of lamps sequentially or
alternatively containing non-split filament lamps 670 and split
filament lamps 680, however, each lamp is spaced further apart from
each other than the lamps in FIGS. 11A-11E.
[0123] In other embodiments, a method for heating a substrate or a
substrate susceptor, such as levitating wafer carrier 480, within a
vapor deposition reactor system, such as reactor 100, by heating
lamp assembly 600 is provided which includes exposing a lower
surface of a substrate susceptor to energy emitted from heating
lamp assembly 600, and heating the substrate susceptor to a
predetermined temperature, wherein heating lamp assembly 600
contains lamp housing 610 disposed on upper surface 606 of support
base 602 and containing at least one lamp holder 620a or 620b, a
plurality of lamps 624 extending from at least one of the lamp
holders, and reflector 650 disposed on upper surface 606 of support
base 602, next to the lamp holder, and below the lamps.
[0124] Embodiments of the method further provide that heating lamp
assembly 600 contains lamps which have split filament lamp 680, a
non-split filament, or a mixture of lamps which contain either
split or non-split filaments. In one embodiment, each of the lamps
has split filament lamp 680. Split filament lamp 680 may have a
center between a first end and a second end. The first and second
ends of split filament lamps 680 may be maintained warmer than the
centers of split filament lamps 680. Therefore, outer edges of the
substrate susceptor may be maintained warmer than a center point of
the substrate susceptor.
[0125] In another embodiment, each of the lamps has non-split
filament lamp 670. Non-split filament lamp 670 may have a center
between a first end and a second end. The centers of non-split
filament lamps 670 may be maintained warmer than the first and
second ends of non-split filament lamps 670. Therefore, a center
point of the substrate susceptor may be maintained warmer than the
outer edges of the substrate susceptor.
[0126] In another embodiment, the plurality of lamps 624 have split
filament lamps and non-split filament lamps. In one embodiment,
split filament lamps 680 and non-split filament lamps 670 are
sequentially disposed between each other. Each lamp may
independently be in electric contact to a power source and a
controller. The method further includes independently adjusting the
amount of electricity flowing to each lamp. In one example, split
filament lamp 680 may have a center between a first end and a
second end. The first and second ends of split filament lamps 680
may be maintained warmer than the centers of split filament lamps
680. Therefore, the outer edges of the substrate susceptor may be
maintained warmer than a center point of the substrate susceptor.
In another example, non-split filament lamp 670 may have a center
between a first end and a second end. The centers of non-split
filament lamps 670 may be maintained warmer than the first and
second ends of non-split filament lamps 670. Therefore, the center
point of the substrate susceptor may be maintained warmer than the
outer edges of the substrate susceptor.
[0127] In various embodiments, the method provides that the
substrate susceptor may be a substrate carrier or a wafer carrier.
Lamp housing 610 may have first lamp holder 620a and second lamp
holder 620b. First lamp holder 620a and second lamp holder 620b may
be parallel or substantially parallel to each other. In one
example, reflector 650 may be disposed between first lamp holder
620a and second lamp holder 620b. First lamp holder 620a and second
lamp holder 620b each have a thickness within a range from about
0.001 inches to about 0.1 inches. The predetermined thickness of
the lamp holders helps maintain a constant temperature of the lamp
holders. Therefore, first lamp holder 620a and second lamp holder
620b may each independently be maintained at a temperature within a
range from about 275.degree. C. to about 375.degree. C.,
preferably, from about 300.degree. C. to about 350.degree. C.
[0128] FIGS. 7A-7D depict showerhead assembly 700 for a vapor
deposition chamber, such as reactor 100, according embodiments
described herein. In one embodiment, showerhead assembly 700
includes body 702 having upper portion 706 and lower portion 704,
and centralized channel 716 extending through upper portion 706 and
lower portion 704 of body 702. Upper portion 706 contains upper
surface 707. Centralized channel 716 extends between inner surfaces
709 of body 702, and parallel to central axis 701 extending through
body 702. Diffusion plate 730 contains a plurality of gas holes 732
and is disposed within centralized channel 716. In one example,
diffusion plate 730 is disposed on a flange or ledge 710. In
another example, showerhead assembly 700 does not contain optional
diffusion plate 730 disposed therein.
[0129] Showerhead assembly 700 further contains upper tube plate
740 having a plurality of gas holes 742 and disposed within
centralized channel 716 below diffusion plate 730. Showerhead
assembly 700 also contains lower tube plate 750 having a plurality
of gas holes 752 and disposed within centralized channel 716 below
upper tube plate 740. A plurality of gas tubes 780 extend from
upper tube plate 740 to lower tube plate 750, wherein each tube is
coupled to and in fluid communication with an individual hole from
the plurality of gas holes 742 and an individual hole from
plurality of gas holes 752. Each of the gas tubes 780 extends
parallel or substantially parallel to each other as well as to
central axis 701 in many embodiments described herein. In an
alternative embodiment, not shown, each of the gas tubes 780 may
extend at a predetermined angle relative to central axis 701, such
as within a range from about 1.degree. to about 15.degree. or
greater.
[0130] Showerhead assembly 700 may be used to disperse gases, such
as purge gases, precursor gases, and/or carrier gases, by providing
a flow path through inlet port 722 and into cavities 738, 748, and
758. Cavity 738 is formed between upper plate 720 and diffusion
plate 730 within centralized channel 716. Cavity 748 is formed
between diffusion plate 730 and upper tube plate 740 within
centralized channel 716. Cavity 758 is formed between upper tube
plate 740 and lower tube plate 750 within centralized channel
716.
[0131] In another embodiment, showerhead assembly 700 includes body
702 containing upper portion 706 and lower portion 704, wherein
upper portion 706 contains a flange extending over lower portion
704, centralized channel 716 extending through upper portion 706
and lower portion 704 of body 702, between inner surfaces 709 of
body 702, and parallel to central axis 701 extending through body
702, diffusion plate 730 containing a plurality of gas holes 732
and disposed within centralized channel 716, upper tube plate 740
containing a plurality of gas holes 742 and disposed within
centralized channel 716 below diffusion plate 730, lower tube plate
750 containing a plurality of gas holes 752 and disposed within
centralized channel 716 below upper tube plate 740, and plurality
of gas tubes 780 extending from upper tube plate 740 to lower tube
plate 750, wherein each tube is coupled to and in fluid
communication with an individual hole from plurality of gas holes
742 and an individual hole from plurality of gas holes 752.
[0132] In another embodiment, showerhead assembly 700 includes body
702 containing upper portion 706 and lower portion 704, wherein
upper portion 706 adjacently extends from central axis 701 of body
702 further than lower portion 704 and lower portion 704 extends
parallel to central axis 701 further than upper portion 706,
centralized channel 716 extending through upper portion 706 and
lower portion 704 of body 702, between inner surfaces 709 of body
702, and parallel to central axis 701, diffusion plate 730
containing a plurality of gas holes 732 and disposed within
centralized channel 716, upper tube plate 740 containing a
plurality of gas holes 742 and disposed within centralized channel
716 below diffusion plate 730, lower tube plate 750 containing a
plurality of gas holes 752 and disposed within centralized channel
716 below upper tube plate 740, and plurality of gas tubes 780
extending from upper tube plate 740 to lower tube plate 750,
wherein each tube is coupled to and in fluid communication with an
individual hole from plurality of gas holes 742 and an individual
hole from plurality of gas holes 752.
[0133] In another embodiment, showerhead assembly 700 includes body
702 containing upper portion 706 and lower portion 704, centralized
channel 716 extending through upper portion 706 and lower portion
704 of body 702, between inner surfaces 709 of body 702, and
parallel to central axis 701 extending through body 702, diffusion
plate 730 containing a plurality of gas holes 732 and disposed
within centralized channel 716, upper tube plate 740 containing a
plurality of gas holes 742 and disposed within centralized channel
716 below diffusion plate 730, and lower tube plate 750 containing
a plurality of gas holes 752 and disposed within centralized
channel 716 below upper tube plate 740.
[0134] In another embodiment, showerhead assembly 700 includes body
702 containing upper portion 706 and lower portion 704, centralized
channel 716 extending through upper portion 706 and lower portion
704 of body 702, between inner surfaces 709 of body 702, and
parallel to central axis 701 extending through body 702, upper tube
plate 740 containing a plurality of gas holes 732 and disposed
within centralized channel 716 below diffusion plate 730, lower
tube plate 750 containing a plurality of gas holes 742 and disposed
within centralized channel 716 below upper tube plate 740, and
plurality of gas tubes 780 extending from upper tube plate 740 to
lower tube plate 750, wherein each tube is coupled to and in fluid
communication with an individual hole from plurality of gas holes
732 and an individual hole from plurality of gas holes 742.
[0135] In some embodiments, showerhead assembly 700 is a modular
showerhead assembly. Upper portion 706 and lower portion 704 of
body 702 may independently contain a material such as steel,
stainless steel, 300 series stainless steel, iron, nickel,
chromium, molybdenum, aluminum, alloys thereof, or combinations
thereof. In one example, upper portion 706 and lower portion 704 of
body 702 each independently contains stainless steel or alloys
thereof.
[0136] In one embodiment, showerhead assembly 700 contains gaseous
inlet 760 disposed on upper portion 706 of body 702. Upper plate
720 may be disposed on an upper surface of upper portion 706 of
body 702 and gaseous inlet 760 may be disposed on the plate. The
plate may contain a material such as steel, stainless steel, 300
series stainless steel, iron, nickel, chromium, molybdenum,
aluminum, alloys thereof, or combinations thereof. In some
examples, the plate has inlet port 722 extending therethrough.
Gaseous inlet 760 has inlet tube 764 extending through inlet port
722. Inlet nozzle 762 may be coupled to one end of inlet tube 764
and disposed above the plate. In another example, the upper surface
of upper portion 706 of the showerhead body has groove 708 which
encompasses centralized channel 716. An O-ring may be disposed
within groove 708. Diffusion plate 730 may be disposed on a ledge
or a flange protruding from side surfaces of body 702 within
centralized channel 716.
[0137] In one embodiment, plurality of gas tubes 780 may have tubes
numbering within a range from about 500 tubes to about 1,500 tubes,
preferably, from about 700 tubes to about 1,200 tubes, and more
preferably, from about 800 tubes to about 1,000 tubes, for example,
about 900 tubes. In some examples, each tube may have a length
within a range from about 0.5 cm to about 2 cm, preferably, from
about 0.8 cm to about 1.2 cm, for example, about 1 cm. In other
examples, each tube may have a diameter within a range from about
0.005 inches to about 0.05 inches, preferably, from about 0.01
inches to about 0.03 inches. In some examples, the tubes are
hypodermic needles. The tubes may contain or be made from a
material such as steel, stainless steel, 300 series stainless
steel, iron, nickel, chromium, molybdenum, aluminum, alloys
thereof, or combinations thereof.
[0138] In one embodiment, each hole of plurality of gas holes 732
on diffusion plate 730 has a larger diameter than each hole of
plurality of gas holes 742 on upper tube plate 740. Further, each
hole of plurality of gas holes 732 on diffusion plate 730 has a
larger diameter than each hole of plurality of gas holes 752 on the
lower diffusion plate. Also, each hole of plurality of gas holes
742 on upper tube plate 740 has the same diameter or substantially
the same diameter as each hole of plurality of gas holes 752 on
lower tube plate 750.
[0139] In one embodiment, diffusion plate 730 may contain or be
made from a material such as steel, stainless steel, 300 series
stainless steel, iron, nickel, chromium, molybdenum, aluminum,
alloys thereof, or combinations thereof. Diffusion plate 730 may
contain holes numbering within a range from about 20 holes to about
200 holes, preferably, from about 25 holes to about 75 holes, and
more preferably, from about 40 holes to about 60 holes. Each hole
of diffusion plate 730 may have a diameter within a range from
about 0.005 inches to about 0.05 inches, preferably, from about
0.01 inches to about 0.03 inches. In another embodiment, upper tube
plate 740 and/or lower tube plate 750 may independently contain or
be independently made from a material such as steel, stainless
steel, 300 series stainless steel, iron, nickel, chromium,
molybdenum, aluminum, alloys thereof, or combinations thereof.
Upper tube plate 740 and/or lower tube plate 750 may independently
have from about 500 holes to about 1,500 holes, preferably, from
about 700 holes to about 1,200 holes, and more preferably, from
about 800 holes to about 1,000 holes. Each hole of upper tube plate
740 and/or lower tube plate 750 may independently have a diameter
within a range from about 0.005 inches to about 0.05 inches,
preferably, from about 0.01 inches to about 0.03 inches. In another
embodiment, showerhead assembly 700 may have a gaseous hole density
and/or number of tubes within a range from about 10 holes/in.sup.2
(holes per square inch) to about 60 holes/in.sup.2, preferably,
from about 15 holes/in.sup.2 to about 45 holes/in.sup.2, and more
preferably, from about 20 holes/in.sup.2 to about 36
holes/in.sup.2.
[0140] In one example, the upper surface of upper portion 706 of
body 702 of showerhead assembly 700 is a metallic plate. In other
examples, showerhead assembly 700 may have a rectangular geometry
or a square geometry. In another embodiment, body 702 of showerhead
assembly 700 further contains a temperature regulation system. The
temperature regulation system, such as temperature regulation
system 190, may contain liquid or fluid passageway 718 extending
within body 702, and may have inlet 714a and outlet 714b coupled to
and in fluid communication with fluid passageway 718. Inlet 714a
and outlet 714b may be independently coupled to and in fluid
communication with a liquid reservoir or at least one heat
exchanger, such as heat exchangers 180a, 180b, or 180c within
temperature regulation system 190, as depicted in FIG. 1F.
[0141] FIGS. 8A-8D depict exhaust assembly 800 for a vapor
deposition chamber, such as reactor 100, according embodiments
described herein. In one embodiment, exhaust assembly 800 includes
body 802 having upper portion 806 and lower portion 804, and
centralized channel 816 extending through upper portion 806 and
lower portion 804 of body 802. Upper portion 806 contains upper
surface 807. Centralized channel 816 extends between inner surfaces
809 of body 802, and parallel to central axis 801 extending through
body 802. Diffusion plate 830 contains a plurality of gas holes 832
and is disposed within centralized channel 816. In one example,
diffusion plate 830 is disposed on a flange or ledge 810. In
another example, exhaust assembly 800 does not contain optional
diffusion plate 830 disposed therein.
[0142] Exhaust assembly 800 further contains upper tube plate 840
having a plurality of gas holes 842 and disposed within centralized
channel 816 below diffusion plate 830. Exhaust assembly 800 also
contains lower tube plate 850 having a plurality of gas holes 854
and disposed within centralized channel 816 below upper tube plate
840. A plurality of exhaust tubes 880 extend from upper tube plate
840 to lower tube plate 850, wherein each tube is coupled to and in
fluid communication with an individual hole from the plurality of
gas holes 842 and an individual hole from plurality of gas holes
854. Each of the exhaust tubes 880 extends parallel or
substantially parallel to each other as well as to central axis 801
in many embodiments described herein. In an alternative embodiment,
each of the exhaust tubes 880 may extend at a predetermined angle
relative to central axis 801, such as within a range from about
1.degree. to about 15.degree. or greater.
[0143] Exhaust assembly 800 pulls a vacuum or reduces internal
pressure though exhaust port 822 and cavities 838, 848, and 858.
Cavity 838 is formed between upper plate 820 and diffusion plate
830 within centralized channel 816. Cavity 848 is formed between
diffusion plate 830 and upper tube plate 840 within centralized
channel 816. Cavity 858 is formed between upper tube plate 840 and
lower tube plate 850 within centralized channel 816.
[0144] In another embodiment, exhaust assembly 800 includes body
802 containing upper portion 806 and lower portion 804, wherein
upper portion 806 contains a flange extending over lower portion
804, centralized channel 816 extending through upper portion 806
and lower portion 804 of body 802, between inner surfaces 809 of
body 802, and parallel to central axis 801 extending through body
802, diffusion plate 830 containing a plurality of gas holes 832
and disposed within centralized channel 816, upper tube plate 840
containing a plurality of gas holes 842 and disposed within
centralized channel 816 below diffusion plate 830, lower tube plate
850 containing a plurality of gas holes 854 and disposed within
centralized channel 816 below upper tube plate 840, and plurality
of exhaust tubes 880 extending from upper tube plate 840 to lower
tube plate 850, wherein each tube is coupled to and in fluid
communication with an individual hole from plurality of gas holes
842 and an individual hole from plurality of gas holes 854.
[0145] In another embodiment, exhaust assembly 800 includes body
802 containing upper portion 806 and lower portion 804, wherein
upper portion 806 adjacently extends from central axis 801 of body
802 further than lower portion 804 and lower portion 804 extends
parallel to central axis 801 further than upper portion 806,
centralized channel 816 extending through upper portion 806 and
lower portion 804 of body 802, between inner surfaces 809 of body
802, and parallel to central axis 801, diffusion plate 830
containing a plurality of gas holes 832 and disposed within
centralized channel 816, upper tube plate 840 containing a
plurality of gas holes 842 and disposed within centralized channel
816 below diffusion plate 830, lower tube plate 850 containing a
plurality of gas holes 854 and disposed within centralized channel
816 below upper tube plate 840, and plurality of exhaust tubes 880
extending from upper tube plate 840 to lower tube plate 850,
wherein each tube is coupled to and in fluid communication with an
individual hole from plurality of gas holes 842 and an individual
hole from plurality of gas holes 854.
[0146] In another embodiment, exhaust assembly 800 includes body
802 containing upper portion 806 and lower portion 804, centralized
channel 816 extending through upper portion 806 and lower portion
804 of body 802, between inner surfaces 809 of body 802, and
parallel to central axis 801 extending through body 802, diffusion
plate 830 containing a plurality of gas holes 832 and disposed
within centralized channel 816, upper tube plate 840 containing a
plurality of gas holes 842 and disposed within centralized channel
816 below diffusion plate 830, and lower tube plate 850 containing
a plurality of gas holes 854 and disposed within centralized
channel 816 below upper tube plate 840.
[0147] In another embodiment, exhaust assembly 800 includes body
802 containing upper portion 806 and lower portion 804, centralized
channel 816 extending through upper portion 806 and lower portion
804 of body 802, between inner surfaces 809 of body 802, and
parallel to central axis 801 extending through body 802, upper tube
plate 840 containing a plurality of gas holes 832 and disposed
within centralized channel 816 below diffusion plate 830, lower
tube plate 850 containing a plurality of gas holes 842 and disposed
within centralized channel 816 below upper tube plate 840, and
plurality of exhaust tubes 880 extending from upper tube plate 840
to lower tube plate 850, wherein each tube is coupled to and in
fluid communication with an individual hole from plurality of gas
holes 832 and an individual hole from plurality of gas holes
842.
[0148] In some embodiments, exhaust assembly 800 is a modular
showerhead assembly. Upper portion 806 and lower portion 804 of
body 802 may independently contain a material such as steel,
stainless steel, 300 series stainless steel, iron, nickel,
chromium, molybdenum, aluminum, alloys thereof, or combinations
thereof. In one example, upper portion 806 and lower portion 804 of
body 802 each independently contains stainless steel or alloys
thereof.
[0149] In one embodiment, exhaust assembly 800 contains exhaust
outlet 860 disposed on upper portion 806 of body 802. Upper plate
820 may be disposed on an upper surface of upper portion 806 of
body 802 and exhaust outlet 860 may be disposed on the plate. The
plate may contain a material such as steel, stainless steel, 300
series stainless steel, iron, nickel, chromium, molybdenum,
aluminum, alloys thereof, or combinations thereof. In some
examples, the plate has exhaust port 822 extending therethrough.
Exhaust outlet 860 has exhaust outlet tube 864 extending through
exhaust port 822. Exhaust nozzle 862 may be coupled to one end of
exhaust outlet tube 864 and disposed above the plate. In another
example, the upper surface of upper portion 806 of the showerhead
body has groove 808 which encompasses centralized channel 816. An
O-ring may be disposed within groove 808. Diffusion plate 830 may
be disposed on a ledge or a flange protruding from side surfaces of
body 802 within centralized channel 816.
[0150] In one embodiment, plurality of exhaust tubes 880 may have
tubes numbering within a range from about 5 tubes to about 50
tubes, preferably, from about 7 tubes to about 30 tubes, and more
preferably, from about 10 tubes to about 20 tubes, for example,
about 14 tubes. In some examples, each tube may have a length
within a range from about 0.5 cm to about 2 cm, preferably, from
about 0.8 cm to about 1.2 cm, for example, about 1 cm. In other
examples, each tube may have a diameter within a range from about
0.1 inches to about 0.4 inches, preferably, from about 0.2 inches
to about 0.3 inches, for example, about 0.23 inches. In one
example, exhaust assembly 800 contains a single row of tubes and
holes.
[0151] In another embodiment, plurality of exhaust tubes 880 may
have tubes numbering within a range from about 500 tubes to about
1,500 tubes, preferably, from about 700 tubes to about 1,200 tubes,
and more preferably, from about 800 tubes to about 1,000 tubes, for
example, about 900 tubes. In some examples, each tube may have a
length within a range from about 0.5 cm to about 2 cm, preferably,
from about 0.8 cm to about 1.2 cm, for example, about 1 cm. In
other examples, each tube may have a diameter within a range from
about 0.005 inches to about 0.05 inches, preferably, from about
0.01 inches to about 0.03 inches.
[0152] In some examples, the tubes are hypodermic needles. The
tubes may contain or be made from a material such as steel,
stainless steel, 300 series stainless steel, iron, nickel,
chromium, molybdenum, aluminum, alloys thereof, or combinations
thereof.
[0153] In one embodiment, each hole of plurality of gas holes 832
on diffusion plate 830 has a larger diameter than each hole of
plurality of gas holes 842 on upper tube plate 840. Further, each
hole of plurality of gas holes 832 on diffusion plate 830 has a
larger diameter than each hole of plurality of gas holes 854 on the
lower diffusion plate. Also, each hole of plurality of gas holes
842 on upper tube plate 840 has the same diameter or substantially
the same diameter as each hole of plurality of gas holes 854 on
lower tube plate 850.
[0154] In one embodiment, diffusion plate 830 may contain or be
made from a material such as steel, stainless steel, 300 series
stainless steel, iron, nickel, chromium, molybdenum, aluminum,
alloys thereof, or combinations thereof. In another embodiment,
diffusion plate 830 may contain holes numbering within a range from
about 5 holes to about 50 holes, preferably, from about 7 holes to
about 30 holes, and more preferably, from about 10 holes to about
20 holes, for example, about 14 holes. Each hole of diffusion plate
830 may have a diameter within a range from about 0.1 inches to
about 0.4 inches, preferably, from about 0.2 inches to about 0.3
inches, for example, about 0.23 inches. In one example, diffusion
plate 830 contains a single row of holes. In another embodiment,
diffusion plate 830 may contain holes numbering within a range from
about 20 holes to about 200 holes, preferably, from about 25 holes
to about 55 holes, and more preferably, from about 40 holes to
about 60 holes. Each hole of diffusion plate 830 may have a
diameter within a range from about 0.005 inches to about 0.05
inches, preferably, from about 0.01 inches to about 0.03
inches.
[0155] In another embodiment, upper tube plate 840 and/or lower
tube plate 850 may independently contain or be independently made
from a material such as steel, stainless steel, 300 series
stainless steel, iron, nickel, chromium, molybdenum, aluminum,
alloys thereof, or combinations thereof. In one embodiment, upper
tube plate 840 and/or lower tube plate 850 may independently have
holes numbering within a range from about 5 holes to about 50
holes, preferably, from about 7 holes to about 30 holes, and more
preferably, from about 10 holes to about 20 holes, for example,
about 14 holes. Each hole of upper tube plate 840 and/or lower tube
plate 850 may independently have a diameter within a range from
about 0.1 inches to about 0.4 inches, preferably, from about 0.2
inches to about 0.3 inches, for example, about 0.23 inches. In
another embodiment, exhaust assembly 800 may have a gaseous hole
density and/or number of tubes within a range from about 5
holes/in.sup.2 (holes per square inch) to about 30 holes/in.sup.2,
preferably, from about 8 holes/in.sup.2 to about 25 holes/in.sup.2,
and more preferably, from about 10 holes/in.sup.2 to about 20
holes/in.sup.2.
[0156] In another embodiment, upper tube plate 840 and/or lower
tube plate 850 may independently have from about 500 holes to about
1,500 holes, preferably, from about 700 holes to about 1,200 holes,
and more preferably, from about 800 holes to about 1,000 holes.
Each hole of upper tube plate 840 and/or lower tube plate 850 may
independently have a diameter within a range from about 0.005
inches to about 0.05 inches, preferably, from about 0.01 inches to
about 0.03 inches.
[0157] In one example, the upper surface of upper portion 806 of
body 802 of exhaust assembly 800 is a metallic plate. In other
examples, exhaust assembly 800 may have a rectangular geometry or a
square geometry. In another embodiment, body 802 of exhaust
assembly 800 further contains a temperature regulation system. The
temperature regulation system, such as temperature regulation
system 190, may contain liquid or fluid passageway 818 extending
within body 802, and may have inlet 814a and outlet 814b coupled to
and in fluid communication with fluid passageway 818. Inlet 814a
and outlet 814b may be independently coupled to and in fluid
communication with a liquid reservoir or at least one heat
exchanger, such as heat exchangers 180a, 180b, or 180c within
temperature regulation system 190, as depicted in FIG. 1F.
[0158] In other embodiments, exhaust assembly 800, which may be
utilized in a vapor deposition chamber, has body 802 containing
upper portion 806 disposed on lower portion 804, centralized
channel 816 extending through upper portion 806 and lower portion
804 of body 802, between inner surfaces 809 of body 802, and
parallel to central axis 801 extending through body 802, exhaust
outlet 860 disposed on upper portion 806 of body 802, diffusion
plate 830 containing a plurality of gas holes 832 and disposed
within centralized channel 816, upper tube plate 840 containing a
plurality of gas holes 842 and disposed within centralized channel
816 below diffusion plate 830, lower tube plate 850 containing a
plurality of gas holes 852 and disposed within centralized channel
816 below upper tube plate 840, and plurality of exhaust tubes 880
extending from upper tube plate 840 to lower tube plate 850,
wherein each tube is coupled to and in fluid communication with an
individual hole from plurality of gas holes 842 and an individual
hole from plurality of gas holes 852.
[0159] Exhaust assembly 800 may further contain upper plate 820
disposed on an upper surface of upper portion 806 of body 802.
Exhaust outlet 860 may be disposed on upper plate 820. Upper plate
820 may contain or be made from a material such as steel, stainless
steel, 300 series stainless steel, iron, nickel, chromium,
molybdenum, aluminum, alloys thereof, or combinations thereof.
Upper plate 820 usually has an exhaust port extending therethrough.
Exhaust outlet 860 may have exhaust outlet tube 864 extending
through exhaust port 822. In one example, exhaust nozzle 862 may be
coupled to one end of exhaust outlet tube 864 and disposed above
upper plate 820. In another example, the upper surface of upper
portion 806 of the exhaust assembly body has groove 808 which
encompasses centralized channel 816. An O-ring may be disposed
within groove 808. Diffusion plate 830 may be disposed on a ledge
or a flange protruding from side surfaces of body 802 within
centralized channel 816.
[0160] FIGS. 9A-9F depict reactor system 1000, a CVD system,
containing multiple reactors 1100a, 1100b, and 1100c, as described
by embodiments herein. Reactors 1100a, 1100b, and 1100c may be the
same reactors as reactor 100 or may be a modified derivative of
reactor 100. In one embodiment, reactor 1100a is coupled to reactor
1100b, which is coupled to reactor 1100c, as illustrated in FIGS.
9A-9C. One end of reactor 1100a is coupled to end cap 1050 at
interface 1012, while the other end of reactor 1100a is coupled to
one end of reactor 1100b at interface 1014. The other end of
reactor 1100b is coupled to one end of reactor 1100c at interface
1016, while the other end of reactor 1100c is coupled to end plate
1002 at interface 1016.
[0161] FIGS. 9D-9F depicts a close-up view of portions of interface
1018 between reactors 1100b and 1100c. In another embodiment,
reactor 1100b contains wafer carrier track 1400 which has lower lap
joint 1450 and reactor 1100c contains wafer carrier track 1400
which has upper lap joint 1440.
[0162] Exhaust purge port 1080 may be disposed between wafer
carrier track 1400 within reactor 1100b and wafer carrier track
1400 within reactor 1100c. Exhaust purge port 1080 is in fluid
communication with passageway 1460, which extends from exhaust
purge port 1080 to below wafer carrier tracks 1400. Exhaust
assembly 1058, similar to exhaust assembly 800, is disposed on the
reactor lid assembly of reactor 1100b. Exhaust assembly 1058 may be
used to remove gases from exhaust purge port 1080. Exhaust assembly
1058 contains exhaust outlet 1060, exhaust nozzle 1062, and exhaust
tube 1064.
[0163] In another embodiment, reactor system 1000 may contain
additional reactors (not shown) besides reactors 1100a, 1100b, and
1100c. In one example, a fourth reactor is included in reactor
system 1000. In another example, a fifth reactor is included in
reactor system 1000. In different configurations and embodiments,
reactor system 1000 may have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more
reactors. In other embodiments, reactors 1100a, 1100b, and 1100c or
other reactors which are not shown, may contain 1, 2, 3, 4, or more
showerhead assemblies in each reactor (not shown).
[0164] In alternative embodiments described herein, other
configurations of reactors 1100a, 1100b, and 1100c are provided,
but not illustrated in the drawings. In one embodiment, each of the
reactors 1100a, 1100b, or 1100c may contain three exhaust
assemblies separated by two showerhead assemblies so that any of
the reactor lid assemblies may sequentially contain a first exhaust
assembly, a first showerhead assembly, a second exhaust assembly, a
second showerhead assembly, and a third exhaust assembly. In
another embodiment, each of the reactors 1100a, 1100b, or 1100c may
contain three isolator assemblies separated by two showerhead
assemblies so that the reactor lid assembly sequentially contain a
first isolator assembly, a first showerhead assembly, a second
isolator assembly, a second showerhead assembly, and a third
isolator assembly.
[0165] In another embodiment, each of the reactors 1100a, 1100b, or
1100c may contain two isolator assemblies and one exhaust assembly
separated by two showerhead assemblies so that any of the reactor
lid assemblies may sequentially contain a first isolator assembly,
a first showerhead assembly, a second isolator assembly, a second
showerhead assembly, and a first exhaust assembly. In another
example, any of the reactor lid assemblies may sequentially contain
a first isolator assembly, a first showerhead assembly, a first
exhaust assembly, a second showerhead assembly, and a second
isolator assembly. In another example, any of the reactor lid
assemblies may sequentially contain a first exhaust assembly, a
first showerhead assembly, a first isolator assembly, a second
showerhead assembly, and a second isolator assembly.
[0166] In another embodiment, each of the reactors 1100a, 1100b, or
1100c may contain two exhaust assemblies and one isolator assembly
separated by two showerhead assemblies so that any of the reactor
lid assemblies may sequentially contain a first exhaust assembly, a
first showerhead assembly, a second exhaust assembly, a second
showerhead assembly, and a first isolator assembly. In another
example, any of the reactor lid assemblies may sequentially contain
a first exhaust assembly, a first showerhead assembly, a first
isolator assembly, a second showerhead assembly, and a second
exhaust assembly. In another example, any of the reactor lid
assemblies may sequentially contain a first isolator assembly, a
first showerhead assembly, a first exhaust assembly, a second
showerhead assembly, and a second exhaust assembly.
[0167] Reactor 100, reactor system 1000, and derivatives of these
reactors may be used for a variety of CVD, MOCVD, and/or epitaxial
deposition processes to form an assortment of materials on wafers
or substrates, as described in embodiments herein. In one
embodiment, a Group III/V material--which contains at least one
element of Group III (e.g., boron, aluminum, gallium, or indium)
and at least one element of Group V (e.g., nitrogen, phosphorous,
arsenic, or antimony) may be formed or deposited on a wafer.
Examples of deposited materials may contain gallium nitride, indium
phosphide, gallium indium phosphide, gallium arsenide, aluminum
gallium arsenide, derivatives thereof, alloys thereof, multi-layers
thereof, or combinations thereof. In some embodiments herein, the
deposited materials may be epitaxial materials. The deposited
material or epitaxial material may contain one layer, but usually
contains multiple layers. In some examples, the epitaxial material
contains a layer having gallium arsenide and another layer having
aluminum gallium arsenide. In another example, the epitaxial
material contains a gallium arsenide buffer layer, an aluminum
gallium arsenide passivation layer, and a gallium arsenide active
layer. The gallium arsenide buffer layer may have a thickness
within a range from about 100 nm to about 500 nm, such as about 300
nm, the aluminum gallium arsenide passivation layer has a thickness
within a range from about 10 nm to about 50 nm, such as about 30
nm, and the gallium arsenide active layer has a thickness within a
range from about 500 nm to about 2,000 nm, such as about 1,000 nm.
In some examples, the epitaxial material further contains a second
aluminum gallium arsenide passivation layer.
[0168] In one embodiment, the process gas used in reactor 100 or
reactor system 1000 may contain arsine, argon, helium, nitrogen,
hydrogen, or mixtures thereof. In one example, the process gas
contains an arsenic precursor, such as arsine. In other
embodiments, the first precursor may contain an aluminum precursor,
a gallium precursor, an indium precursor, or combinations thereof,
and the second precursor may contain a nitrogen precursor, a
phosphorus precursor, an arsenic precursor, an antimony precursor
or combinations thereof.
[0169] In one embodiment, the CVD reactor may be configured to
supply nitrogen to the reactor to float the substrate along the
track of the reactor at the entrance and the exit. A
hydrogen/arsine mixture may also be used to float the substrate
along the track of the CVD reactor between the exit and entrance.
The stages along the track may include an entrance nitrogen
isolation zone, a preheat exhaust, a hydrogen/arsine mixture
preheat isolation zone, a gallium arsenide deposition zone, a
gallium arsenide exhaust, an aluminum gallium arsenide deposition
zone, a gallium arsenide N-layer deposition zone, a gallium
arsenide P-layer deposition zone, a phosphorous hydrogen arsine
isolation zone, a first phosphorous aluminum gallium arsenide
deposition zone, a phosphorous aluminum gallium arsenide exhaust, a
second phosphorous aluminum gallium arsenide deposition zone, a
hydrogen/arsine mixture cool down isolation zone, a cool down
exhaust, and an exit nitrogen isolation zone. The temperature of
the substrate traveling through the reactor may be increased while
passing the entrance isolation zone, or may be maintained while
traveling through the zones, or may be decreased while nearing the
arsine cool down isolation zone.
[0170] In another embodiment, the CVD reactor may be configured to
supply nitrogen to the reactor to float the substrate along the
track of the reactor at the entrance and the exit. A
hydrogen/arsine mixture may also be used to float the substrate
along the track of the CVD reactor between the exit and entrance.
The stages along the track may include an entrance nitrogen
isolation zone, a preheat exhaust, a hydrogen/arsine mixture
preheat isolation zone, an exhaust, a deposition zone, an exhaust,
a hydrogen/arsine mixture cool down isolation zone, a cool down
exhaust, and an exit nitrogen isolation zone. The temperature of
the substrate traveling through the reactor system may be increased
as is passes the entrance isolation zone, may be maintained as is
travels through the deposition zone, and may be decreased as it
nears the arsine cool down isolation zone.
[0171] In another embodiment, the CVD reactor may be configured to
supply nitrogen to the reactor to float the substrate along the
track of the reactor at the entrance and the exit. A
hydrogen/arsine mixture may also be used to float the substrate
along the track of the CVD reactor between the exit and entrance.
The stages along the track may include an entrance nitrogen
isolation zone, a preheat exhaust with flow balance restrictor, an
active hydrogen/arsine mixture isolation zone, a gallium arsenide
deposition zone, an aluminum gallium arsenide deposition zone, a
gallium arsenide N-layer deposition zone, a gallium arsenide
P-layer deposition zone, a phosphorous aluminum gallium arsenide
deposition zone, a cool down exhaust, and an exit nitrogen
isolation zone. The temperature of the substrate traveling through
the reactor may increase while passing the entrance isolation zone,
or may be maintained while traveling through the deposition zones,
or may be decreased while nearing the cool down exhaust.
[0172] In another embodiment, the CVD reactor may be configured to
supply nitrogen to the reactor to float the substrate along the
track of the reactor at the entrance and the exit. A
hydrogen/arsine mixture may also be used to float the substrate
along the track of the CVD reactor between the exit and entrance.
The stages along the track may include an entrance nitrogen
isolation zone, a preheat exhaust with flow balance restrictor, a
gallium arsenide deposition zone, an aluminum gallium arsenide
deposition zone, a gallium arsenide N-layer deposition zone, a
gallium arsenide P-layer deposition zone, a phosphorous aluminum
gallium arsenide deposition zone, a cool down exhaust with flow
balance restrictor, and an exit nitrogen isolation zone. The
temperature of the substrate traveling through the reactor may be
increased while passing the entrance isolation zone, or may be
maintained while traveling through the deposition zones, or may be
decreased while nearing the cool down exhaust.
[0173] FIG. 17 illustrates a seventh configuration 800. The CVD
reactor may be configured to supply nitrogen to the reactor to
float the substrate along the track of the reactor at the entrance
and the exit. A hydrogen/arsine mixture may also be used to float
the substrate along the track of the CVD reactor between the exit
and entrance. The stages along the track may include an entrance
nitrogen isolation zone, a preheat exhaust, a deposition zone, a
cool down exhaust, and an exit nitrogen isolation zone. The
temperature of the substrate traveling through the reactor may be
increased while passing the entrance isolation zone, or may be
maintained while traveling through the deposition zone, or may be
decreased while nearing the cool down exhaust.
[0174] In one embodiment, the CVD reactor may be configured to
epitaxially grow a double hetero-structure containing gallium
arsenide materials and aluminum gallium arsenide materials, as well
as to epitaxially grow a lateral overgrowth sacrificial layer
containing aluminum arsenide materials. In some examples, the
gallium arsenide, aluminum gallium arsenide, and aluminum arsenide
materials may be deposited at a rate of about 1 .mu.m/min. In some
embodiments, the CVD reactor may have a throughput of about 6
wafers per minute to about 10 wafers per minute.
[0175] In an embodiment, the CVD reactor may be configured to
provide a deposition rate of one 10 cm by 10 cm substrate per
minute. In one embodiment the CVD reactor may be configured to
provide a 300 nm gallium arsenide buffer layer. In one embodiment
the CVD reactor may be configured to provide a 30 nm aluminum
gallium arsenide passivation layer. In one embodiment the CVD
reactor may be configured to provide a 1,000 nm gallium arsenide
active layer. In one embodiment the CVD reactor may be configured
to provide a 30 nm aluminum gallium arsenide passivation layer. In
one embodiment the CVD reactor may be configured to provide a
dislocation density of less than 1.times.10.sup.4 per centimeter
squared, a photoluminescence efficiency of 99%; and a
photoluminescence lifetime of 250 nanoseconds.
[0176] In one embodiment the CVD reactor may be configured to
provide an epitaxial lateral overgrowth layer having a 5 nm
deposition +-0.5 nm; a etch selectivity greater than
1.times.10.sup.6; zero pinholes; and an aluminum arsenide etch rate
greater than 0.2 mm per hour.
[0177] In one embodiment the CVD reactor may be configured to
provide a center to edge temperature non-uniformity of no greater
than 10.degree. C. for temperatures above 300.degree. C.; a V-III
ratio of no more than 5; and a maximum temperature of 700.degree.
C.
[0178] In one embodiment the CVD reactor may be configured to
provide a deposition layers having a 300 nm gallium arsenide buffer
layer; a 5 nm aluminum arsenide sacrificial layer; a 10 nm aluminum
gallium arsenide window layer; a 700 nm gallium arsenide
1.times.10.sup.17 Si active layer; a 300 nm aluminum gallium
arsenide 1.times.10.sup.19 C P+ layer; and a 300 nm gallium
arsenide 1.times.10.sup.19 C P+ layer.
[0179] In one embodiment the CVD reactor may be configured to
provide a deposition layers having a 300 nm gallium arsenide buffer
layer; a 5 nm aluminum arsenide sacrificial layer; a 10 nm gallium
indium phosphide window layer; a 700 nm gallium arsenide
1.times.10.sup.17 Si active layer; a 100 nm gallium arsenide C P
layer; a 300 nm gallium indium phosphide P window layer; a 20 nm
gallium indium phosphide 1.times.10.sup.20 P+ tunnel junction
layer; a 20 nm gallium indium phosphide 1.times.10.sup.20 N+ tunnel
junction layer; a 30 nm aluminum gallium arsenide window; a 400 nm
gallium indium phosphide N active layer; a 100 nm gallium indium
phosphide P active layer; a 30 nm aluminum gallium arsenide P
window; and a 300 nm gallium arsenide P+ contact layer.
[0180] While the foregoing is directed to embodiments of the
invention, other and further embodiments of the invention may be
devised without departing from the basic scope thereof, and the
scope thereof is determined by the claims that follow.
* * * * *