U.S. patent application number 10/496667 was filed with the patent office on 2005-01-13 for zn based semiconductor luminiscent element and method for preparation thereof.
Invention is credited to Ishizaki, Jun-ya.
Application Number | 20050009223 10/496667 |
Document ID | / |
Family ID | 19175564 |
Filed Date | 2005-01-13 |
United States Patent
Application |
20050009223 |
Kind Code |
A1 |
Ishizaki, Jun-ya |
January 13, 2005 |
Zn based semiconductor luminiscent element and method for
preparation thereof
Abstract
A p-n junction interface 3 is formed between an n-type
ZnTe.sub.1-xO.sub.x (0.5.ltoreq.x.ltoreq.1) layer 8 and a p-type
ZnTe.sub.1-xO.sub.x (0.ltoreq.x<0.5) layer 7, and the n-type
ZnTeO layer 8 and/or p-type ZnTeO layer 7 are formed by thermal
oxidation of the main surficial side of a p-type ZnTe wafer. This
is successful in providing a Zn-base semiconductor light emitting
device and a method of fabricating thereof possibly be improved in
the emission efficiency at a light emitting layer composed of a
Zn-base semiconductor light emitting device.
Inventors: |
Ishizaki, Jun-ya;
(Annaka-shi, JP) |
Correspondence
Address: |
Ronal R Snider
P O Box 27613
Washington
DC
20038-7613
US
|
Family ID: |
19175564 |
Appl. No.: |
10/496667 |
Filed: |
May 25, 2004 |
PCT Filed: |
November 1, 2002 |
PCT NO: |
PCT/JP02/11426 |
Current U.S.
Class: |
438/47 ; 257/102;
257/96; 438/46 |
Current CPC
Class: |
H01L 33/0083 20130101;
H01L 33/28 20130101 |
Class at
Publication: |
438/047 ;
438/046; 257/102; 257/096 |
International
Class: |
H01L 021/00; H01L
033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 30, 2001 |
JP |
2001-365557 |
Claims
1. A Zn-base semiconductor light emitting device comprising a
light-emitting region in which a p-n junction is formed by an
interface between an n-type layer and a p-type layer; the n-type
layer being a Zn-base semiconductor composed of Zn as a Group II
element, and O or a combination of O and Te as Group VI element(s);
and the p-type layer being a Zn-base semiconductor having a Te
content larger than that of the n-type layer.
2. The Zn-base semiconductor light emitting device as claimed in
claim 1, wherein the p-type layer is a Zn-base semiconductor
composed of ZnTe.
3. The Zn-base semiconductor light emitting device as claimed in
claim 1, wherein the p-type layer is a Zn-base semiconductor
composed of Zn as a Group II element, and O and Te as Group VI
elements.
4. A method of fabricating a Zn-base semiconductor light emitting
device comprising a step of annealing a p-type ZnTe wafer in an
oxidative atmosphere, to thereby form an n-type layer, which is a
Zn-base semiconductor composed of Zn as a Group II element, and O
or a combination of O and Te as Group VI element(s), and to
consequently form a p-n junction therebetween.
5. A method of fabricating a Zn-base semiconductor light emitting
device having a light emitting region in which a p-n junction is
formed at an interface between an n-type layer composed of ZnO, and
a p-type layer composed of Zn as a Group II element, and O or a
combination of O and Te as Group VI element(s); wherein the method
comprises a step of formation-by-stacking of the n-type layer on
the main surface of the p-type ZnTe wafer.
6. A method of fabricating a Zn-base semiconductor light emitting
device having a light emitting region in which a p-n junction is
formed at an interface between an n-type layer composed of ZnO, and
a p-type layer composed of Zn as a Group II element, and O or a
combination of O and Te as Group VI element(s); wherein the method
comprises a step of formation-by-stacking of the n-type layer on
the main surface of the p-type ZnTe wafer, after being annealed
under an oxygen atmosphere.
7. The method of fabricating a Zn-base semiconductor light emitting
device as claimed in claim 5, wherein the formation-by-stacking is
based on the vapor-phase epitaxy process or deposition process.
8. The method of fabricating a Zn-base semiconductor light emitting
device as claimed in claim 6, wherein the formation-by-stacking is
based on the vapor-phase epitaxy process or deposition process.
Description
TECHNICAL FIELD
[0001] This invention relates to a Zn-base semiconductor light
emitting device and a method of fabricating the same, and in
particular to a Zn-base semiconductor light emitting device adapted
to blue to green visible wavelength band, and a method of
fabricating the same.
BACKGROUND ART
[0002] It is generally believed as difficult to arbitrarily control
conductivity type of II-VI compound semiconductors having Zn (zinc)
as a Group II element in the periodic table (Zn-base semiconductor)
due to self-compensation effect caused by formation of intrinsic
defect. Under such circumference of Zn-base semiconductor, a recent
effort has been succeeded in obtaining an n-type ZnTe (zinc
telluride), having Te (tellurium) as a group VI element in the
periodic table, and having a small band gap energy which belongs to
green wavelength band, and in fabricating a light emitting device
based on homo-junction using ZnTe.
[0003] The above-described light emitting device based on
homo-junction using ZnTe, however, suffers from a suppressed
emission efficiency, because ZnTe intrinsically has p-type
conductivity in its non-doped state, has a lower carrier
concentration in the n-type layer than in the p-type layer, and
carriers can uniformly diffuse in the vicinity of a p-n junction
interface to be formed.
[0004] One possible way to raise the emission efficiency is such as
forming a double heterostructure in which an active layer is
typically composed of ZnTe, and cladding layers are composed of a
Zn-base semiconductor containing ZnTe. Formation of the double
heterostructure is generally proceeded by vapor phase epitaxy such
as the epitaxial growth process, but formation of the double
heterostructure using a ZnTe wafer as a substrate, for example, may
raise production costs higher than that in the formation of a p-n
junction interface based on homo-junction using the ZnTe wafer.
[0005] While not being limited for the cases of ZnTe, it is
important subjects for any light emitting devices having a light
emitting region composed of a Zn-base semiconductor, of which
conductivity type is believed to be less controllable, to raise the
emission efficiency based on an effective carrier injection into
the light emitting region, and to raise the luminance of light to
be extracted.
[0006] This invention was conceived taking the above-described
subjects into consideration. In other words, it is therefore an
object of this invention to provide a Zn-base semiconductor light
emitting device which is possibly raised in the emission efficiency
in a light emitting region composed of Zn-base semiconductor, and
to provide a method of fabricating the same.
DISCLOSURE OF THE INVENTION
[0007] A Zn-base semiconductor light emitting device of this
invention aimed at solving the above-described subjects is
characterized in comprising a light-emitting region in which a p-n
junction is formed by an interface between an n-type layer and a
p-type layer; the n-type layer being a Zn-base semiconductor
composed of Zn as a Group II element, and O or a combination of O
and Te as Group VI element(s); and the p-type layer being a Zn-base
semiconductor having a Te content larger than that of the n-type
layer.
[0008] It is to be noted that the Zn-base semiconductor in this
patent specification means an alloyed compound ZnTe.sub.1-xO.sub.x
(0.ltoreq.x.ltoreq.1) of ZnTe and ZnO, where ZnTe and ZnO (zinc
oxide) also inclusive.
[0009] In the above-described Zn-base semiconductor in a non-doped
state, ZnO (zinc oxide) shows a conductivity type of n-type, ZnTe
(zinc telluride) shows p-type, alloyed compound ZnTe.sub.1-xO.sub.x
(0.ltoreq.x.ltoreq.1) of ZnTe and ZnO shows p-type for a ZnO alloy
composition x of 0.ltoreq.x<0.5, and n-type for a ZnO alloy
composition x of 0.5.ltoreq.x.ltoreq.1. In this invention, the
p-type layer is configured using p-type ZnTe.sub.1-xO.sub.x
(0.ltoreq.x<0.5) (also simply referred to as p-type ZnTeO,
hereinafter), and the n-type layer is configured using n-type
ZnTe.sub.1-xO.sub.x (0.5.ltoreq.x.ltoreq.1) (also simply referred
to as n-type ZnTeO, hereinafter), and the light emitting region is
formed by the p-n junction interface between the p-type layer and
n-type layer.
[0010] By forming the light emitting region using the Zn-base
semiconductor adjustable either to n-type and p-type under
non-doped state, it is made possible to inject carriers into the
light emitting region more effectively than in the conventional
homo-junction-type light emitting device composed of a Zn-base
semiconductor represented by ZnTe, and to thereby improve the
emission efficiency.
[0011] Next, the p-type layer of the Zn-base semiconductor light
emitting device of this invention is characterized in that it is
composed of ZnTe. By configuring the p-type layer using ZnTe, it is
made possible to adjust the emission obtainable from the light
emitting region so as to have an emission wavelength equivalent to
green, and to raise the emission efficiency as compared with the
conventional homo-junction-type light emitting device composed of
ZnTe.
[0012] In addition, it is still also possible to adjust the
emission wavelength obtainable from the light emitting region, by
adjusting the ZnO alloy composition x of the p-type ZnTeO composing
the p-type layer. In an exemplary case where the p-type layer is
composed of ZnTe.sub.0.68O.sub.0.32 (x=0.32), an emission
wavelength equivalent to blue (approximately 500 nm) can be
obtained from the light emitting region. As described in the above,
it is made possible to obtain, from the light emitting region,
light emission at a visible wavelength shorter than green, by
configuring the p-type layer using p-type ZnTeO except ZnO.
[0013] A first aspect of a method of fabricating a Zn-base
semiconductor light emitting device, the device having a p-n
junction formed between an n-type layer which is a Zn-base
semiconductor composed of Zn as a Group II element, and O or a
combination of O and Te as Group VI element(s), and a p-type layer
which is a Zn-base semiconductor having a Te content larger than
that of the n-type layer, characterized in having a step of
annealing a p-type ZnTe wafer in an oxidative atmosphere, to
thereby form an n-type layer, which is a Zn-base semiconductor
composed of Zn as a Group II element, and O or a combination of O
and Te as Group VI element(s), and to consequently form a p-n
junction therebetween.
[0014] By loading the p-type ZnTe wafer into an annealing furnace
and annealing it under the oxidative atmosphere (thermal
oxidation), Te sites in the main surficial side of the p-type ZnTe
wafer is substituted by O (oxygen), and ZnO having a conductivity
type of n-type are formed. In this process, the ZnO-base
semiconductors composing the p-type layer and n-type layer at the
p-n junction interface are determined by the number of Te sites
substituted by O. Referring now to schematic drawings in FIGS. 4A
to 4C, in an exemplary case where all of the Te sites on the
n-type-layer side of the p-n junction interface are substituted by
O, the p-n junction interface 3 is formed between the n-type ZnO
layer 1 and a p-type ZnTe layer 2 (FIG. 4A). On the other hand, in
the case where the Te sites on the n-type-layer side of the p-n
junction interface are partially substituted by O, the p-n junction
interface 3 is formed between an n-type ZnTeO layer 4 composed of
n-type ZnTeO exclusive of ZnO, and the p-type ZnTe layer 2 (FIG.
4B). For the case where the Te sites are partially substituted by
O, another possible case may be such that the n-type layer
composing the p-n junction interface 3 will be the n-type ZnO layer
1 composed of ZnO, and the p-type layer will be a p-type ZnTeO
layer 5 composed of p-type ZnTeO exclusive of ZnTe. The number of
Te sites substituted by O, which determines the Zn-base
semiconductors composing the p-type layer and n-type layer at the
p-n junction interface is adjustable depending on temperature and
process time of the thermal oxidation process.
[0015] By subjecting the p-type ZnTe wafer to the thermal oxidation
process, it is made possible to readily form the p-n junction
interface between the n-type ZnTeO layer composed of n-type
ZnTe.sub.1-xO.sub.x (0.5.ltoreq.x.ltoreq.1) and the p-type ZnTeO
layer composed of p-type ZnTe.sub.1-xO.sub.x (0.ltoreq.x<0.5).
Because the carriers can be injected more efficiently into the
n-type ZnTeO layer than into the p-type ZnTeO layer, it is made
possible to improve the emission efficiency of visible light
emission ranging over green to blue regions at the p-type ZnTeO
layer in the vicinity of the p-n junction interface, as compared
with that in a light emitting device based on homo-junction
composed of a Zn-base semiconductor such as ZnTe.
[0016] A second aspect of a method of fabricating a Zn-base
semiconductor light emitting device, the device having a p-n
junction formed between an n-type layer which is a Zn-base
semiconductor composed of Zn as a Group II element, and O or a
combination of O and Te as Group VI element(s), and a p-type layer
which is a Zn-base semiconductor having a Te content larger than
that of the n-type layer,
[0017] characterized in that the n-type layer is composed of ZnO,
and in comprising a step of formation-by-stacking of the n-type
layer on the main surface of the p-type ZnTe wafer.
[0018] As shown in FIG. 3A, by the formation-by-stacking of ZnO
having an n-type conductivity on the main surface of the p-type
ZnTe wafer, the p-n junction interface 3 can be formed at the
interface between the p-type ZnTe layer 2 and an n-type ZnO layer
6. The p-n junction interface 3 formed by formation-by-stacking of
the n-type ZnO layer 6 as described in the above is more successful
in suppressing disturbance at the interface as compared with the
p-n junction interface 3 shown in FIG. 4A, formed by the
above-described thermal oxidation process. This is consequently
successful in suppressing scattering of the carriers or generation
of non-radiative center at the p-n junction interface 3 shown in
FIG. 3A, and is further successful in improving emission efficiency
in green light emission obtainable from the p-type ZnTe layer
2.
[0019] As a third aspect of a method of fabricating a Zn-base
semiconductor light emitting device, other than the above-described
second aspect, it is also allowable to form the p-n junction
interface 3 between the p-type ZnTeO layer 5 and n-type ZnO layer 6
as shown in FIG. 3B, by forming the p-type ZnTeO (exclusive of
ZnTe) layer 5 by thermal oxidation of the surficial portion of the
p-type ZnTe wafer, and then stacking thereon ZnO having an n-type
conductivity. In this case, light emission in the visible
wavelength band ranging from green to blue can be obtained by
adjusting ZnO alloy composition of ZnTeO composing the p-type ZnTeO
layer 5 depending on temperature and process time of the thermal
oxidation process.
[0020] In the above-described second and third aspects of the
method of fabricating a Zn-base semiconductor light emitting device
of this invention, the formation-by-stacking of n-type ZnO can be
proceeded by the vapor-phase epitaxy process or deposition process.
The aforementioned formation-by-stacking of n-type ZnO also makes
it possible to adjust the thickness of the n-type ZnO layer 6 more
easily than in the method of the first aspect in which the n-type
ZnO layer 1 is formed by the thermal oxidation process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a schematic sectional view showing one embodiment
of a Zn-base semiconductor light emitting device according to this
invention;
[0022] FIG. 2 is a schematic sectional view of an essential portion
of the Zn-base semiconductor light emitting device showing one
embodiment of this invention;
[0023] FIG. 3A is a first schematic drawing for explaining the
Zn-base semiconductor light emitting device of this invention,
formed by the vapor-phase epitaxy process or deposition
process;
[0024] FIG. 3B is a second schematic drawing for explaining the
same;
[0025] FIG. 4A is a first schematic drawing for explaining the
Zn-base semiconductor light emitting device of this invention,
formed by the thermal oxidation process;
[0026] FIG. 4B is a second schematic drawing of the same; and
[0027] FIG. 4C is a third schematic drawing of the same.
BEST MODES FOR CARRYING OUT THE INVENTION
[0028] The following paragraphs will describe best modes for
carrying out this invention referring to the attached drawings.
[0029] FIG. 2 is a schematic sectional view showing an essential
portion of the Zn-base semiconductor light emitting device
according to one embodiment of this invention. As described in the
above, alloyed compound ZnTe.sub.1-xO.sub.x (0.ltoreq.x.ltoreq.1)
of ZnTe and ZnO will be p-type ZnTeO showing a p-type conductivity
for a ZnO alloy composition x of 0.ltoreq.x<0.5, and will be
n-type ZnTeO showing an n-type conductivity for a ZnO alloy
composition x of 0.5.ltoreq.x.ltoreq.1. The p-n junction interface
3 shown in FIG. 2 is composed of a p-type ZnTeO layer 7 composed of
p-type ZnTeO and an n-type ZnTeO layer 8 composed of n-type ZnTeO.
The conventional light emitting device in which a homo-junction was
configured using Zn-base semiconductor such as ZnTe was suffering
from a problem in that an effective carrier injection was
suppressed due to difficulty in controlling the conductivity type
of the Zn-base semiconductor. On the contrary, because the n-type
ZnTeO layer 8 and p-type ZnTeO layer 7 composing the p-n junction
interface 3 shown in FIG. 2 are composed of Zn-base semiconductors
showing n-type and p-type conductivities, respectively, in their
non-doped state, it is made possible for the n-type ZnTeO layer 8
to effectively inject carriers into a light emitting region 9. This
is consequently successful in raising the light emission efficiency
at the light emitting region 9.
[0030] It is also made possible to allow the light emitting region
9 to emit a wide range of visible light over green to blue region
through adjustment of the ZnO alloy composition of p-type ZnTeO
composing the p-type ZnTeO layer 7.
[0031] The n-type ZnTeO layer 8 and/or p-type ZnTeO layer 7 shown
in FIG. 2 can be formed by a fabrication method in which the main
surficial side of the p-type ZnTe wafer is subjected to thermal
oxidation. Process steps for the fabrication will be explained in
the next.
[0032] The main surface of the p-type ZnTe wafer is cleaned by
acetone solvent cleaning for removing organic matters, by rinsing
with pure water, and by drying. Thereafter the p-type ZnTe wafer is
loaded in a thermal oxidation furnace, annealed within a
temperature range from 350.degree. C. to 700.degree. C. under an
oxygen atmosphere so as to substitute the Te sites with 0, to
thereby form the n-type ZnTeO layer 8 and/or p-type ZnTeO layer 7
shown in FIG. 2.
[0033] The process temperature in the thermal oxidation process
below 350.degree. C. is undesirable because the thermal oxidation
process for substituting the Te sites with O will not fully
function, and on the other hand, the annealing temperature higher
than 700.degree. C. will be causative of dissipation of O once
substituting the Te sites. The thermal oxidation is therefore
preferably carried out within a temperature range from 350.degree.
C. to 700.degree. C. Because the number of the Te sites
substitutable with O increases as the process temperature of the
thermal oxidation raises, adjustment of the process temperature
within the above-described temperature range and of process time
will be successful in properly determining the Zn-base
semiconductor composing the p-type layer and/or n-type layer by
which the p-n junction interface 3 is formed as shown in FIGS. 4A
to 4C.
[0034] By forming the p-n junction interface 3 between the p-type
layer and n-type layer composed of a Zn-base semiconductor by the
fabrication method based on the thermal oxidation, the carriers can
be injected more efficiently into the p-type ZnTeO layer 7 rather
than into the n-type ZnTeO layer 8. This is successful in raising
the emission efficiency of visible light emission ranging over
green to blue regions at the light emitting region 9, as compared
with that of the conventional light emitting device based on
homo-junction composed of a Zn-base semiconductor.
[0035] It is also possible to form the n-type ZnTeO layer 8 shown
in FIG. 2 by vapor-phase epitaxy or deposition of n-type ZnTeO.
Formation of the n-type ZnTeO layer 8 by vapor-phase epitaxy or
deposition of n-type ZnTeO is more successful in suppressing
disturbance at the p-n junction interface 3 as compared with the
case where the n-type ZnTeO layer 8 is formed by the
above-described thermal oxidation process. This is consequently
successful in suppressing scattering of the carriers or generation
of non-luminescent center at the p-n junction interface 3, and is
further successful in improving emission efficiency of light
emission obtainable from the p-type ZnTeO layer 7. Another
advantage of forming the n-type ZnTeO layer 8 by the vapor-phase
epitaxy or deposition of n-type ZnTeO resides in that the thickness
of the n-type ZnTeO layer 8 can more readily be controlled than in
the fabrication method based on the above-described thermal
oxidation process.
[0036] In the fabrication process for forming the n-type ZnTeO
layer 8 based on vapor-phase epitaxy of n-type ZnTeO, the n-type
ZnTeO layer 8 can be formed by cleaning the main surface of the
p-type ZnTe wafer according to a process step similar to that in
the fabrication method based on the above-described thermal
oxidation process, by loading the p-type ZnTe wafer into a reaction
furnace for vapor-phase epitaxy, and by stacking n-type ZnTeO on
the main surface of the p-type ZnTe wafer. For the purpose of
forming the p-n junction interface 3 using the Zn-base
semiconductor as shown in FIG. 3B, it is also allowable to form,
before formation of the n-type ZnTeO layer 8, the p-type ZnTeO
layer (where, ZnTe exclusive) in the main surficial layer of the
p-type ZnTe wafer by thermal oxidation of the main surficial side
thereof, and then to form the n-type ZnTeO layer 8 on the main
surface thereof.
[0037] The above-described, vapor-phase epitaxy of n-type ZnTeO can
be carried out by vapor-phase epitaxy process such as MOVPE (Metal
Organic Vapor Phase Epitaxy) process, or MBE (Molecular Beam
Epitaxy) process. It is to be noted that MBE described in this
patent specification not only means MBE in a narrow sense using
both of the metal element component source and non-metal element
component source in a solid state, but conceptually includes MOMBE
(Metal Organic Molecular Beam Epitaxy) using the metal element
component in a form of organic metal and using the non-metal
element component source in a solid state; gas source MBE using the
metal element component source in a solid state and the non-metal
element component source in a gas state; and chemical beam epitaxy
(CBE (Chemical Beam Epitaxy)) using the metal element component
source in a form of organic metal and using the non-metal element
component source in a gas form.
[0038] For the case where the MOVPE process is typically adopted as
the aforementioned vapor-phase epitaxy process, major raw materials
for n-type ZnTeO composing the n-type ZnTeO layer 8 shown in FIG. 2
include the followings:
[0039] Oxygen component source gas: preferably supplied in a form
of an oxidative compound gas in view of suppressing excessive
reaction with organo-metallic gases described later, although
supply in a form of oxygen gas also allowable. Specific examples
include N.sub.2O, NO, NO.sub.2 and CO. N.sub.2O (nitrous oxide) is
used in this embodiment;
[0040] Te source gas: diethyl tellurium (DETe), etc.; and
[0041] Zn source (metal component source) gas: dimethyl zinc
(DMZn), diethyl zinc (DEZn), etc.
[0042] The n-type ZnTeO layer 8 can be formed by the vapor-phase
epitaxy of n-type ZnTeO using the above-described major source
materials under a temperature atmosphere of 300.degree. C. to
800.degree. C. or around to a thickness of approximately 1 to 20
.mu.m. For the purpose of relaxing lattice mismatching between the
p-type ZnTeO for composing the p-type ZnTeO layer 7 and the n-type
ZnTeO, it is also allowable in this process to form n-type ZnTeO by
the vapor-phase epitaxy at a relatively low temperature ranging
from 300.degree. C. to 500.degree. C. or around to a thickness of
approximately 5 to 50 nm, which is smaller than the critical film
thickness, and then to further form n-type ZnTeO by the vapor-phase
epitaxy under a temperature atmosphere at a temperature elevated to
as high as 400.degree. C. to 800.degree. C. or around, so as to
form the n-type ZnTeO layer 8 to a thickness of approximately 1 to
20 .mu.m. Adoption of this method is successful in improving the
crystallinity of the n-type ZnTeO layer 8, consequently improving
the n-type conductivity of the n-type ZnTeO layer 8, and in
effectively injecting the carriers into the light emitting region
9.
[0043] Referring now to the thickness of the above-described n-type
ZnTeO layer 8 formed by the vapor-phase epitaxy, a resultant
thickness of smaller than 1 .mu.m will fail in injecting a
necessary number of carriers from the n-type ZnTeO layer 8 into the
light emitting region 9. On the other hand, the thickness of the
n-type ZnTeO layer 8 exceeding 20 .mu.m will be expectant of
effectively injecting the carriers from the n-type ZnTeO layer 8
into the light emitting region 9, and of enhancing the light
extraction effect from the side faces of the light emitting device,
but too excessive thickness will be causative of increase in the
production cost. It is therefore preferable to suppress the
thickness of the n-type ZnTeO layer 8 to as small as 20 .mu.m or
less. Because n-type ZnTeO composing the n-type ZnTeO layer 8 has a
refractive index of as small as 2.0 or around, and can ensure a
large critical angle of total reflection at the interface of the
main surface of the n-type ZnTeO layer 8 and the air for the case
where the light emission obtained from the light emitting region 9
is extracted mainly through the n-type ZnTeO layer 8, it is
possible to fully extract the light from the main surface of the
n-type ZnTeO layer 8 even if the thickness thereof is adjusted to
as small as 20 .mu.m or below. Considering the above, the thickness
of the n-type ZnTeO layer 8 is preferably adjusted to 1 .mu.m to 20
.mu.m, both ends inclusive.
[0044] In the formation of the n-type ZnTeO layer 8, it is also
possible to dope n-type carriers by adding any one, or two or more
species of Al, Ga and In as n-type dopant(s). Examples of the
available dopants include the followings:
[0045] Al source gas: trimethyl aluminum (TMAI), triethyl aluminum
(TEAI), etc.;
[0046] Ga source gas: trimethyl gallium (TMGa), triethyl gallium
(TEGa), etc.; and
[0047] In source gas: trimethyl indium (TMIn), triethyl indium
(TEIn), etc.
[0048] For the case where the n-type ZnTeO is deposited to form the
n-type ZnTeO layer 8, the deposition may also be proceeded by other
deposition process such as sputtering, besides the aforementioned
vapor-phase epitaxy.
[0049] After completion of the stacked structure shown in FIG. 2
according to the fabrication method described in the above, an
n-type electrode 10 composed of Al and a p-type electrode 11
composed of In are formed as shown in FIG. 1 to thereby obtain a
Zn-base semiconductor light emitting device 100 allowing light
extraction from the n-type-electrode side.
* * * * *