U.S. patent application number 15/210420 was filed with the patent office on 2016-11-03 for method of forming fins from different materials on a substrate.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Stanley Seungchul SONG, Zhongze WANG, Choh Fei YEAP.
Application Number | 20160322391 15/210420 |
Document ID | / |
Family ID | 51352812 |
Filed Date | 2016-11-03 |
United States Patent
Application |
20160322391 |
Kind Code |
A1 |
SONG; Stanley Seungchul ; et
al. |
November 3, 2016 |
METHOD OF FORMING FINS FROM DIFFERENT MATERIALS ON A SUBSTRATE
Abstract
A method of forming fins of different materials includes
providing a substrate with a layer of a first material having a top
surface, masking a first portion of the substrate leaving a second
portion of the substrate exposed, etching a first opening at the
second portion, forming a body of a second material in the opening
to a level of the top surface of the layer of the first material,
removing the mask, and forming fins of the first material at the
first portion and forming fins of the second material at the second
portion. A finFET device having fins formed of at least two
different materials is also disclosed.
Inventors: |
SONG; Stanley Seungchul;
(San Diego, CA) ; WANG; Zhongze; (San Diego,
CA) ; YEAP; Choh Fei; (San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
51352812 |
Appl. No.: |
15/210420 |
Filed: |
July 14, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13956398 |
Aug 1, 2013 |
9396931 |
|
|
15210420 |
|
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/845 20130101;
H01L 27/1211 20130101; H01L 21/02365 20130101; H01L 29/20 20130101;
H01L 29/1033 20130101; H01L 29/1037 20130101; H01L 21/823431
20130101; H01L 21/8258 20130101; H01L 27/1207 20130101; H01L 29/16
20130101; H01L 29/785 20130101 |
International
Class: |
H01L 27/12 20060101
H01L027/12; H01L 21/84 20060101 H01L021/84; H01L 29/20 20060101
H01L029/20; H01L 29/10 20060101 H01L029/10; H01L 29/16 20060101
H01L029/16 |
Claims
1. A finFEt device having fins formed of at least two different
materials comprising: a substrate having a first layer having a top
surface; a first oxide layer on the first layer top surface, the
first oxide layer having a top surface, the first oxide layer
covering a first portion of the first layer and not covering a
second portion of the first layer; a first body of material at the
second portion of the first layer, the first body of material
having a top surface even with the top surface of the first oxide
layer; a first set of fins formed of a first material on the first
oxide layer; and a second set of fins formed of a second material
on the first body of material.
2. The FinFET device of claim 1, wherein the first layer comprises
the second material.
3. The finFET device of claim 1, wherein the substrate comprises a
third material different than the first material and the second
material.
4. The finFEt device of claim 3, wherein the second material
comprises germanium.
5. The finFET device of claim 3, wherein the substrate comprises a
second layer and a second oxide layer on the second layer, wherein
the first layer is located on the second oxide layer, and including
a second body of material extending from the second layer through
the second oxide layer, the first layer and the first oxide layer,
the second body of material having a top surface even with the top
surface of the first oxide layer, the second body of material and
the second layer being formed of a third material, and a third set
of fins formed of the third material on the second body of
material.
6. The finFET device of claim 5, wherein the second material
comprises germanium and the third material comprises silicon.
7. The finFET device of claim 6 integrated into at least one
semiconductor die.
8. The finFET device of claim 7, wherein the at least one
semiconductor die is incorporated into a device selected from a
group consisting of a set top box, music player, video player,
entertainment unit, navigation device, communications device,
personal digital assistant (PDA), fixed location data unit, and a
computer.
9. The finFET device of claim 1 integrated into at least one
semiconductor die.
10. The finFET device of claim 1, wherein the finFET device is
incorporate into a device selected from a group consisting of a set
top box, music player, video player, entertainment unit, navigation
device, communications device, personal digital assistant (PDA),
fixed location data unit, and a computer.
11. A finFEt device having fins formed of at least two different
materials comprising: a substrate having a first layer having a top
surface; a first oxide layer on the first layer top surface, the
first oxide layer having a top surface, the first oxide layer
covering a first portion of the first layer and not covering a
second portion of the first layer; a first body of material at the
second portion of the first layer, the first body of material
having a top surface even with the top surface of the first oxide
layer; first means for forming a first portion of a semiconductor
device; and second means for forming a second portion of a
semiconductor device.
12. The FinFET device of claim 11, wherein the first layer
comprises the second material.
13. The finFET device of claim 11, wherein the substrate comprises
a third material different than the first material and the second
material.
14. The finFEt device of claim 13, wherein the second material
comprises germanium.
15. The finFET device of claim 13, wherein the substrate comprises
a second layer and a second oxide layer on the second layer,
wherein the first layer is located on the second oxide layer, and
including a second body of material extending from the second layer
through the second oxide layer, the first layer and the first oxide
layer, the second body of material having a top surface even with
the top surface of the first oxide layer, the second body of
material and the second layer being formed of a third material, and
a third set of fins formed of the third material on the second body
of material.
16. The finFET device of claim 15, wherein the second material
comprises germanium and the third material comprises silicon.
17. The finFET device of claim 16 integrated into at least one
semiconductor die.
18. The finFET device of claim 17, wherein the at least one
semiconductor die is incorporated into a device selected from a
group consisting of a set top box, music player, video player,
entertainment unit, navigation device, communications device,
personal digital assistant (PDA), fixed location data unit, and a
computer.
17. The finFET device of claim 11 integrated into at least one
semiconductor die.
18. The finFET device of claim 11, wherein the finFET device is
incorporated into a device selected from a group consisting of a
set top box, music player, video player, entertainment unit,
navigation device, communications device, personal digital
assistant (PDA), fixed location data unit, and a computer.
Description
CLAIM OF PRIORITY UNDER 35 U.S.C. .sctn.120
[0001] The present Application for Patent is a divisional of, and
claims priority to, U.S. patent application Ser. No. 13/956,398,
entitled "METHOD OF FORMING FINS FROM DIFFERENT MATERIALS ON A
SUBSTRATE," filed Aug. 1, 2013, pending, assigned to the assignee
hereof, and expressly incorporated herein by reference in its
entirety.
FIELD OF THE DISCLOSURE
[0002] The present disclosure is directed to a method of forming
fins from different materials on a substrate and to a substrate
having fins formed from different materials and, more specifically,
toward a method of forming fins on a multi-layer substrate wherein
some of the fins are formed from the material of a first layer of
the substrate and some of the fins are formed from a material of a
second layer of the substrate and toward a substrate having such
fins.
BACKGROUND
[0003] FinFET devices include a plurality of fins that may be used
to form channels of a finFET transistor. It is sometimes desirable
to form the fins from different materials. For example, it may be
desirable to form some fins from a Group III-Group V material,
indium arsenide or indium gallium arsenide, for example, another
group of fins from germanium and, optionally, a third group of
silicon fins. In order to form fins from different materials, it
has heretofore been necessary to form an appropriate buffer layer
for the particular layer of fin material on a layer of silicon to
provide a suitable substrate on which to grow a given type of
material. This is relatively easy when fins are all formed from the
same material. However, forming fins from two or three different
materials requires two or three buffer layers, and this complicates
the substrate manufacturing process. It would therefore be
desirable to produce fins from different materials in an efficient
manner.
SUMMARY
[0004] An exemplary embodiment includes a method of forming fins of
different materials. The method includes providing a substrate
comprising a layer of a first material having a top surface,
masking a first portion of the substrate to form a mask while
leaving a second portion of the substrate exposed, and etching a
first opening at the second portion. The method also includes
forming a body of a second material in the opening to a level of
the top surface of the layer of the first material, removing the
mask and forming fins of the first material at the first portion
and forming fins of the second material at the second portion.
[0005] Another embodiment includes a finFEt device having fins
formed of at least two different materials. The device comprises a
substrate having a first layer having a top surface and a first
oxide layer on the first layer top surface. The first oxide layer
has a top surface, and the first oxide layer covers a first portion
of the first layer and does not cover a second portion of the first
layer. A first body of material is formed at the second portion of
the first layer, and the first body of material has a top surface
even with the top surface of the first oxide layer. A first set of
fins is formed of a first material on the first oxide layer, and a
second set of fins formed of a second material is formed on the
first body of material.
[0006] An additional embodiment includes a method of forming fins
of different materials. The method includes providing a substrate
comprising a layer of a first material, a first oxide layer on the
layer of the first material, a layer of a second material on the
first oxide layer, and a second oxide layer on the layer of the
second material. The substrate also includes a layer of a third
material on the second oxide layer, and the layer of the third
material has a top surface that forms a top surface of the
substrate. The method also includes etching a first opening at a
first location on the substrate through the layer of the third
material and through the second oxide layer to the layer of the
second material and forming a body of the second material in the
first opening to a level of the top surface of the substrate. The
method also includes etching a second opening at a second location
on the substrate through the layer of the third material, the
second oxide layer, the layer of the second material and the first
oxide layer to the layer of the first material and forming a body
of the first material in the second opening to a level of the top
surface of the substrate. In addition, the method includes forming
first fins comprising the second material at the first location,
forming second fins comprising the first material at the second
location and forming third fins comprising the third material at a
third location.
[0007] Another embodiment includes a method of forming fins of
different materials. The method includes steps for providing a
substrate comprising a layer of a first material having a top
surface, steps for masking a first portion of the substrate to form
a mask while leaving a second portion of the substrate exposed, and
steps for etching a first opening at the second portion. The method
also includes steps for forming a body of a second material in the
opening to a level of the top surface of the layer of the first
material, steps for removing the mask, and steps for forming fins
of the first material at the first portion and forming fins of the
second material at the second portion.
[0008] An additional embodiment includes a finFEt device having
fins formed of at least two different materials. The device
comprises a substrate having a first layer having a top surface and
a first oxide layer on the first layer top surface, the first oxide
layer having a top surface. The first oxide layer covers a first
portion of the first layer and does not cover a second portion of
the first layer. A first body of material is formed at the second
portion of the first layer, the first body of material having a top
surface even with the top surface of the first oxide layer. First
fin means for forming a first portion of a semiconductor device are
provided, and second fin means for forming a second portion of a
semiconductor device are provided.
[0009] Another embodiment includes a method of forming fins of
different materials. The method includes steps for providing a
substrate comprising a layer of a first material, a first oxide
layer on the layer of the first material, a layer of a second
material on the first oxide layer, a second oxide layer on the
layer of the second material and a layer of a third material on the
second oxide layer. The layer of the third material has a top
surface forming a top surface of the substrate. The method also
includes steps for etching a first opening at a first location on
the substrate through the layer of the third material and through
the second oxide layer to the layer of the second material and
steps for forming a body of the second material in the first
opening to a level of the top surface of the substrate. The method
also includes steps for etching a second opening at a second
location on the substrate through the layer of the third material,
the second oxide layer, the layer of the second material and the
first oxide layer to the layer of the first material and steps for
forming a body of the first material in the second opening to a
level of the top surface of the substrate. In addition, the method
includes steps for forming first fins comprising the second
material at the first location, steps for forming second fins
comprising the first material at the second location and steps for
forming third fins comprising the third material at a third
location.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The accompanying drawings are presented to aid in the
description of embodiments of the invention and are provided solely
for illustration of the embodiments and not limitation thereof.
[0011] FIGS. 1-8 are elevational views schematically showing a
wafer during different processing stages according to a first
embodiment.
[0012] FIGS. 9-15 are elevational views schematically showing a
wafer during processing stages according to a second
embodiment.
[0013] FIGS. 16-23 are elevational views schematically showing a
wafer during processing stages according to a third embodiment.
[0014] FIGS. 24-31 are elevational views schematically showing a
wafer during processing stages according to a fourth
embodiment.
[0015] FIGS. 32-45 are elevational views schematically showing a
wafer during processing stages according to a fifth embodiment.
[0016] FIGS. 46-52 are elevational views schematically showing a
wafer during processing stages according to a sixth embodiment.
[0017] FIG. 53 is a flowchart illustrating a method according to an
embodiment.
[0018] FIG. 54 is a flowchart illustrating a method according to
another embodiment.
[0019] FIG. 55 is a schematic diagram of an exemplary wireless
communication system in which embodiments of the disclosure may be
used.
DETAILED DESCRIPTION
[0020] Aspects of the invention are disclosed in the following
description and related drawings directed to specific embodiments
of the invention. Alternate embodiments may be devised without
departing from the scope of the invention. Additionally, well-known
elements of the invention will not be described in detail or will
be omitted so as not to obscure the relevant details of the
invention.
[0021] The word "exemplary" is used herein to mean "serving as an
example, instance, or illustration." Any embodiment described
herein as "exemplary" is not necessarily to be construed as
preferred or advantageous over other embodiments. Likewise, the
term "embodiments of the invention" does not require that all
embodiments of the invention include the discussed feature,
advantage or mode of operation.
[0022] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
embodiments of the invention. As used herein, the singular forms
"a", "an" and "the" are intended to include the plural forms as
well, unless the context clearly indicates otherwise. It will be
further understood that the terms "comprises", "comprising",
"includes", and/or "including", when used herein, specify the
presence of stated features, integers, steps, operations, elements,
and/or components, but do not preclude the presence or addition of
one or more other features, integers, steps, operations, elements,
components, and/or groups thereof.
[0023] Further, many embodiments are described in terms of
sequences of actions to be performed by, for example, elements of a
computing device. It will be recognized that various actions
described herein can be performed by specific circuits (e.g.,
application specific integrated circuits (ASICs)), by program
instructions being executed by one or more processors, or by a
combination of both. Additionally, these sequence of actions
described herein can be considered to be embodied entirely within
any form of computer readable storage medium having stored therein
a corresponding set of computer instructions that upon execution
would cause an associated processor to perform the functionality
described herein. Thus, the various aspects of the invention may be
embodied in a number of different forms, all of which have been
contemplated to be within the scope of the claimed subject matter.
In addition, for each of the embodiments described herein, the
corresponding form of any such embodiments may be described herein
as, for example, "logic configured to" perform the described
action.
[0024] FIG. 1 is a substrate 100 comprising a silicon layer 102
having a top surface 104. In FIG. 2, a nitride hardmask 200 having
a top surface 202 has been applied to a first portion 204 of the
substrate 100 leaving a second portion 206 of the substrate 100
unmasked. In FIG. 3, an etching process has formed an opening 300
in the substrate 100 at the unmasked second portion 206 of the
substrate. FIG. 4 shows a silicon-germanium ("SiGe") layer 400 that
is grown or otherwise formed on the substrate 100 in the opening
300 and over the top surface 202 of the nitride hardmask 200.
Beneficially, SiGe can be grown directly on silicon without forming
a separate buffer layer. In FIG. 5, the SiGe layer 400 has been
chemically and/or mechanically removed down to the level of the top
surface 202 of the nitride hardmask 200. Oxidizing SiGe causes it
to condense, and multiple oxidation processes reduce the height of
the SiGe layer 400 until a top surface 402 of the SiGe layer 400 is
even with the top surface 104 of the silicon layer 102, as
illustrated in FIG. 6, and the nitride hardmask 200 is removed as
shown in FIG. 7. The result is a structure 700 comprising the
silicon layer 102 with the body 400 of SiGe contained therein. A
plurality of fins 800 are formed in the structure 700 in a
conventional manner as illustrated in FIG. 8. A first subset 802 of
the fins are formed of the silicon layer 102, and a second subset
804 of the fins are formed from the body 400 of SiGe. A finFET
device (not illustrated) can be formed, on a semiconductor die, for
example, from the device of FIG. 8, which finFET device will have
some fins formed of silicon and other fins formed of germanium.
[0025] A process according to a second embodiment is illustrated in
FIGS. 9-15. FIG. 9 illustrates a substrate 900 that includes a
silicon layer 902 having a top surface 904, a bottom oxide layer
906 on the top surface 904 of the silicon layer 902 and a top layer
908 formed of a Group III-V material such as indium arsenide or
indium gallium arsenide which substrate 900 may be referred to
generally as a "Group III-V on insulator." The top layer 908 has a
top surface 910. In FIG. 10, a nitride hardmask 1000 having a top
surface 1002 is applied to a first portion 1004 the top surface 910
of the top layer 908 leaving a second portion 1006 of the top layer
908 exposed. As illustrated in FIG. 11, the top layer 908 and the
bottom oxide layer 906 are etched to form an opening 1100 down to
the level of the top surface 904 of the silicon layer 902. In FIG.
12, a SiGe layer 1200 is grown or otherwise formed in the opening
1100 and on the top surface 1002 of the nitride hardmask 1000. As
in the first embodiment, the SiGe layer 1200 can be grown directly
on the silicon layer 902 without the use of a buffer layer. The
SiGe layer 1200 is mechanically and/or chemically modified to
remove the portions thereof that are not in or over the opening
1100, and the SiGe layer 1200 is thereafter oxidized to reduce its
thickness to the level of the top surface 910 of the top layer 908
as illustrated in FIG. 13. The nitride hardmask 1000 is removed as
shown in FIG. 14 leaving a substrate 1400 comprising the top layer
908 of Group III-V material with a body 1200 of SiGe in the top
layer 908. In FIG. 15, fins 1500 are formed from the substrate 1400
including a first subset of fins 1502 formed from the Group III-V
material and a second subset of fins 1504 formed from SiGe. A
finFET device (not illustrated) can be formed from the device of
FIG. 15, which finFET device will have some fins formed of the
Group III-V material and other fins formed of SiGe.
[0026] A process according to a third embodiment is illustrated in
FIGS. 16-23. In FIG. 16, a substrate 1600 is provided that includes
a germanium bottom layer 1602 having a top surface 1604 and an
oxide layer 1606 on the top surface 1604 of the bottom layer 1602.
A Group III-V top layer 1608 is formed on the oxide layer 1606 and
has a top surface 1610. In FIG. 17, a nitride hardmask 1700 having
a top surface 1702 is applied to a first portion 1704 of the top
layer 1608 leaving a second portion 1706 exposed. In FIG. 18, the
top layer 1608 and the oxide layer 1606 are etched down to the top
surface 1604 of the germanium bottom layer 1602 to form an opening
1800. FIG. 19 shows a body 1900 of germanium non-selectively
epitaxially deposited in the opening 1800 and over the top surface
1702 of the nitride hardmask 1700. Because the bottom layer 1602
and the body 1900 are both germanium, it is not necessary to use
SiGe and, instead, the germanium of the body 1900 can be grown
directly on the top surface 1604 of the bottom layer 1602. FIG. 20
illustrates a substrate 2000 after a chemical mechanical polishing
process has removed the portion of the body 1900 of germanium that
was outside the opening 1800, and in FIG. 21, the body 1900 of
germanium in the opening 1800 is oxidized and etched to reduce its
thickness to a level of the top surface 1610 of the top layer 1608.
The nitride hardmask 1700 is removed in FIG. 22 to produce a
substrate 2200 having a body 1900 of germanium surrounded by the
Group III-V material of the top layer 1608. This substrate 2200 is
processed to form fins 2300 in FIG. 23, a first subset 2302 of
which are formed of the Group III-V material and a second subset
2304 of which are formed of germanium from the body 1900. A finFET
device (not illustrated) can be formed from the device of FIG. 23,
which finFET device will have some fins formed of the Group III-V
material and other fins formed of germanium.
[0027] A process according to a fourth embodiment is illustrated in
FIGS. 24-31. FIG. 24 illustrates a substrate 2400 having a silicon
layer 2402 having a top surface 2404, a first oxide layer 2406, a
germanium layer 2408 having a top surface 2410 on the first oxide
layer 2406, a second oxide layer 2412 on the top surface 2410, and
a Group III-V top layer 2414 having a top surface 2416. In FIG. 25,
a nitride hardmask 2500 having a top surface 2502 is applied to a
first portion 2504 of the top layer 2414 leaving a second portion
2506 of the top layer 2414 exposed. In FIG. 26, the top layer 2414
and the second oxide layer 2412 are etched at the second portion
2506 down to the top surface 2410 of the germanium layer 2408 to
form an opening 2600. As shown in FIG. 27, a body 2700 of germanium
is grown in the opening 2600 which extends out of the opening 2600
and onto the top surface 2502 of the nitride hardmask 2500. Because
the body 2700 of germanium is grown on a germanium layer 2408, a
separate buffer layer is not required. Thereafter, as illustrated
in FIG. 28, the portion of body 2700 on the top surface 2502 of the
nitride hardmask 2500 is chemically and/or mechanically removed,
and, in FIG. 29, the body 2700 of germanium is oxidized and etched
to reduce its thickness to the level of the top surface 2416 of the
top layer 2414. In FIG. 30 the nitride hardmask 2500 is removed
leaving a substrate 3000 comprising the top layer 2414 of the Group
III-V material with a germanium body 2700 therein. The substrate
3000 is processed in a conventional manner to form fins 3100
illustrated in FIG. 31, a first subset 3102 of which are formed of
the Group III-V material and a second subset 3104 of which are
formed of germanium from the body 2700 of germanium. A finFET
device (not illustrated) can be formed from the device of FIG. 31,
which finFET device will have some fins formed of the Group III-V
material and other fins formed of germanium.
[0028] From the foregoing description, it will be appreciated that
the embodiment of FIGS. 24-31 are somewhat similar to the
embodiment of FIGS. 16-23. However, providing a silicon substrate
2400 for the germanium layer 2408 allows the substrate to be
handled with conventional equipment for processing silicon while
still providing a germanium layer 2408 on which to grow the
germanium body 2700. The substrate 1600 of FIGS. 16-23 can be used
to form fins in a manner similar to the method of FIGS. 24-31 but,
because it includes a germanium bottom layer 1602, the substrate
1600 must be processed by equipment specifically configured to
handle germanium, which material is typically more fragile that
silicon and more difficult to handle.
[0029] FIGS. 32-45 illustrate a process according to a fifth
embodiment, in which fins of three different materials are formed
on a substrate. FIG. 32 illustrates a substrate 3200 having a
silicon layer 3202 having a top surface 3204, a first oxide layer
3206, a germanium layer 3208 having a top surface 3210 on the first
oxide layer 3206, a second oxide layer 3212 on the top surface
3210, and a Group III-V top layer 3214 having a top surface 3216.
In FIG. 33, a nitride hardmask 3300 having a top surface 3302 is
applied to a first portion 3304 of the top layer 3214 leaving a
second portion 3306 of the top layer 3214 exposed. In FIG. 34, the
top layer 3214 and the second oxide layer 3212 are etched at the
second portion 3306 down to the top surface 3210 of the germanium
layer 3208 to form an opening 3400. FIG. 35 illustrates a body 3500
of germanium grown in the opening 3400 which extends out of the
opening 3400 and onto the top surface 3302 of the nitride hardmask
3300. Because the body 3500 of germanium is grown on a germanium
layer 3208, a separate buffer layer is not required. Thereafter, as
illustrated in FIG. 36, the portion of body 3500 on the top surface
3302 of the nitride hardmask 3300 is chemically and/or mechanically
removed, and, in FIG. 37 the body 3500 of germanium is oxidized and
etched to reduce its thickness to the level of the top surface 3216
of the top layer 3214. In FIG. 38 the nitride hardmask 3300 is
removed leaving a substrate comprising the top layer 3214 of the
Group III-V material with a germanium body 3500 therein, the
substrate having a top surface comprising the top of the top layer
3214 of Group III-V material.
[0030] To this point, the process of the fifth embodiment is
similar to the process of the fourth embodiment. However, after the
substrate having a germanium body 3500 therein is formed, in the
present embodiment, as illustrated in FIG. 39, a second nitride
hard mask 3900 having a top surface 3902 is formed on the top
surface 3802 of the substrate leaving a third portion 3904 at a
location spaced from the second portion 3306 exposed. As
illustrated in FIG. 40, the top layer 3214, the second oxide layer
3212, the germanium layer 3208 and the first oxide layer 3206 are
etched to form an opening 4000 that extends to the top surface 3204
of the silicon layer 3202, and in FIG. 41, a body of silicon 4100
is formed on the top surface 3204 of the silicon layer 3202 which
fills the opening 4000 and covers the top surface 3902 of the
nitride hardmask 3900. The body of silicon 4100 is chemically
and/or mechanically removed from the top surface 3902 of the
nitride hardmask and oxidized, as illustrated in FIG. 43, until it
is at the level of the top surface 3216 of the top layer 3214. The
second nitride hardmask 3900 is removed, as illustrated in FIG. 44,
leaving a substrate 4400 having a first region 3500 of germanium
and a second region 4100 of silicon in the top layer 3214 of Group
III-V material. This substrate 4400 is processed in a conventional
manner to form a plurality of fins 4500, illustrated in FIG. 45. A
first subset 4502 of the fins 4500 comprise the Group III-V
material, a second subset 4504 of the fins 4500 comprise germanium
from the germanium body 3500, and a third subset 4506 of the fins
4500 comprise silicon from the second region 4100 of silicon.
Growing the germanium on the existing germanium layer 3208 and
growing the silicon on the silicon layer 3202 allows the formation
of three different types of fins for use in a finFET (not
illustrated) without the need to form a buffer layer for each of
the different materials.
[0031] FIGS. 46-51 illustrate a method according to a sixth
embodiment. In this embodiment, with reference to FIG. 46, a
silicon substrate 4600 has a silicon layer 4602 having a top
surface 4604, a first oxide layer 4606 on the top surface 4604, a
germanium layer 4608 on the first oxide layer 4606 and having a top
surface 4610, a second oxide layer 4612 on the top surface 4610 of
the germanium layer 4608. A top layer 4614 comprising a Group III-V
material and having a top surface 4616 is formed on the second
oxide layer 4612. A nitride hardmask 4618 having a top surface 4620
is formed on the top surface 4616 of the top layer 4614. This
structure is generally similar to the structure of FIG. 33.
However, in the previous embodiment, a location for forming fins of
silicon was determined independently of the location for forming
fins of germanium. The present embodiment allows more precise
control of the relative locations of these two sets of fins. To
this end, a top mask layer 4622 is applied to the top surface 4620
of the nitride hardmask 4618 with a first opening 4624 at a
location for forming germanium fins and a second opening 4626 at a
location for forming silicon fins, and, as illustrated in FIG. 47,
a first opening 4700 is etched in the nitride hardmask 4618 at the
first opening 4624, and a second opening 4702 is etched in the
nitride hardmask 4618 at the second opening 4626. In FIG. 48, the
first opening is filled with a shield body of material 4800, a
bottom anti-reflective material (BARC) or a photoresist or organic
carbon containing film, for example, which could be formed by spin
coating followed by a lithographic and development process.
Alternately, the body of material 4800 could comprise carbon-doped
SiO.sub.x and be deposited by a plasma enhanced chemical vapor
deposition (PECVD) process followed by lithographic process and
etch. At the second opening 4626 the substrate 4600 is etched
through the top layer 4614, the second oxide layer 4612, the
germanium layer 4608 and the first oxide layer 4606 to the silicon
layer 4602, forming an opening 4802. In FIG. 49, a body 4900 of
silicon is grown in the opening 4802 up to the top mask layer 4622.
Subsequently, as illustrated in FIG. 50, the shield body of
material 4800 is removed, and an opening 5002 is formed at the
first opening 4624 of the top mask layer 4622. At this additional
opening 5002, the top layer 4614 and second oxide layer 4612 are
etched to the level of the germanium layer 4608, and, as illustrate
in FIG. 51, a body 5102 of germanium is grown in the opening 5002
up to the top mask layer 4622. The top mask layer 4622 and the
nitride hardmask 4618 are then removed to leave a substrate 5200
having a germanium body 5102 and a silicon body 4900 each
surrounded by the top layer 4614 formed of the Group III-V
material, which substrate can be formed into a substrate having
three different types of fins substantially as shown in FIG.
45.
[0032] A method according to an embodiment is illustrated in FIG.
53 and includes a block 5300 of providing a substrate comprising a
layer of a first material having a top surface, a block 5302 of
masking a first portion of the substrate leaving a second portion
of the substrate exposed, a block 5304 of etching a first opening
at the second portion, a block 5306 of forming a body of a second
material in the opening to a level of the top surface of the layer
of the first material, a block 5308 of removing the mask and a
block 5310 of forming fins of the first material at the first
portion and forming fins of the second material at the second
portion.
[0033] Another method according to an embodiment is illustrated in
FIG. 54 and includes a block 5400 of providing a substrate
comprising a layer of a first material, a first oxide layer on the
layer of the first material, a layer of a second material on the
first oxide layer, a second oxide layer on the layer of the second
material and a layer of a third material on the second oxide layer,
the layer of the third material having a top surface forming a top
surface of the substrate. The method also includes a block 5402 of
etching a first opening at a first location on the substrate
through the layer of the third material and through the second
oxide layer to the layer of the second material, a block 5404 of
forming a body of the second material in the first opening to a
level of the top surface of the substrate, a block 5406 of etching
a second opening at a second location on the substrate through the
layer of the third material, the second oxide layer, the layer of
the second material and the first oxide layer to the layer of the
first material, a block 5408 of forming a body of the first
material in the second opening to a level of the top surface of the
substrate and a block 5410 of forming first fins comprising the
second material at the first location, forming second fins
comprising the first material at the second location and forming
third fins comprising the third material at a third location.
[0034] FIG. 55 illustrates an exemplary wireless communication
system 5500 in which one or more embodiments of the disclosure may
be advantageously employed. For purposes of illustration, FIG. 55
shows three remote units 5520, 5530, and 5550 and two base stations
5540. It will be recognized that conventional wireless
communication systems may have many more remote units and base
stations. The remote units 5520, 5530, and 5550 include integrated
circuit or other semiconductor devices 5525, 5535 and 5555
(including finFET's having fins of different materials as disclosed
herein), which are among embodiments of the disclosure as discussed
further below. FIG. 55 shows forward link signals 5580 from the
base stations 5540 and the remote units 5520, 5530, and 5550 and
reverse link signals 5590 from the remote units 5520, 5530, and
5550 to the base stations 5540.
[0035] In FIG. 55, the remote unit 5520 is shown as a mobile
telephone, the remote unit 5530 is shown as a portable computer,
and the remote unit 5550 is shown as a fixed location remote unit
in a wireless local loop system. For example, the remote units may
be any one or combination of a mobile phone, hand-held personal
communication system (PCS) unit, portable data unit such as a
personal data or digital assistant (PDA), navigation device (such
as GPS enabled devices), set top box, music player, video player,
entertainment unit, fixed location data unit such as meter reading
equipment, or any other device that stores or retrieves data or
computer instructions, or any combination thereof. Although FIG. 55
illustrates remote units according to the teachings of the
disclosure, the disclosure is not limited to these exemplary
illustrated units. Embodiments of the disclosure may be suitably
employed in any device having active integrated circuitry including
memory and on-chip circuitry for test and characterization.
[0036] Further, those of skill in the art will appreciate that the
various illustrative logical blocks, modules, circuits, and
algorithm steps described in connection with the embodiments
disclosed herein may be implemented as electronic hardware,
computer software, or combinations of both. To clearly illustrate
this interchangeability of hardware and software, various
illustrative components, blocks, modules, circuits, and steps have
been described above generally in terms of their functionality.
Whether such functionality is implemented as hardware or software
depends upon the particular application and design constraints
imposed on the overall system. Skilled artisans may implement the
described functionality in varying ways for each particular
application, but such implementation decisions should not be
interpreted as causing a departure from the scope of the present
invention.
[0037] The methods, sequences and/or algorithms described in
connection with the embodiments disclosed herein may be embodied
directly in hardware, in a software module executed by a processor,
or in a combination of the two. A software module may reside in RAM
memory, flash memory, ROM memory, EPROM memory, EEPROM memory,
registers, hard disk, a removable disk, a CD-ROM, or any other form
of storage medium known in the art. An exemplary storage medium is
coupled to the processor such that the processor can read
information from, and write information to, the storage medium. In
the alternative, the storage medium may be integral to the
processor.
[0038] Accordingly, an embodiment of the invention can include a
computer readable media embodying a method for forming a substrate
having fins of different materials. Accordingly, the invention is
not limited to illustrated examples and any means for performing
the functionality described herein are included in embodiments of
the invention.
[0039] While the foregoing disclosure shows illustrative
embodiments of the invention, it should be noted that various
changes and modifications could be made herein without departing
from the scope of the invention as defined by the appended claims.
The functions, steps and/or actions of the method claims in
accordance with the embodiments of the invention described herein
need not be performed in any particular order. Furthermore,
although elements of the invention may be described or claimed in
the singular, the plural is contemplated unless limitation to the
singular is explicitly stated.
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