JP2001024221A - Gallium nitride compound semiconductor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve crystallinity and optical properties, etc., of a GaN layer formed in an MOVPE method. SOLUTION: On an AlN buffer layer provided on a sapphire board, a GaN or AlGaN compound semiconductor is film-formed in an organometallic compound vapor growth (MOVPE) method. In this case, an In dope GaN film or an A1GaN film for constitution is provided with a-axis lattice constant and c-axis lattice constant (where an a-axis and a c-axis satisfy substantially relation between distortion and stress of bulk GaN or A1xGa1-xN) between a value of lattice constant of a GaN film or a AlxGa1-xN film formed in the MOVPE method and a value of lattice constant of bulk GaN or AlxGa1-xN.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gallium nitride-based compound semiconductor used for a blue light emitting diode, a blue laser diode and the like formed by a metal organic compound vapor phase epitaxy (MOVPE) method and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, GaN has been used as a semiconductor material for blue light emitting diodes, blue laser diodes, and the like.
Attention has been focused on compound semiconductors such as AlGaN-based, GaInN-based, and the like. The GaN single crystal thin film is usually formed by MOVPE, in which, for example, an organic metal such as trimethylgallium (TMG), trimethylaluminum (TMA), or ammonia is supplied as a carrier gas using a hydrogen gas as a carrier gas and epitaxially grown on a sapphire substrate. can get. When AlGaN, GaN, or the like is formed by the MOVPE method, a method of adding Mg and Zn as acceptor impurities that form a light emission center in a short wavelength region is also known.

However, sapphire and GaN of the substrate have a large lattice constant mismatch and a large difference in thermal expansion coefficient, and when a GaN film is grown directly on the sapphire substrate, pits in the grown film, cracks at the interface between the grown film and the substrate, and the like. In addition to the macro defects described above, there are problems such as spatial micro fluctuations in the crystal orientation.
It is not easy to produce a high quality GaN single crystal thin film with a flat surface.

[0004] The present inventors have previously proposed a substrate temperature of 850-1.
It has been found that the above problem can be solved by depositing AlN on a sapphire substrate at a low temperature of about 600 ° C. immediately before the growth of the GaN film at 030 ° C. and using this as a buffer layer.
According to this method, the free electron concentration at room temperature is as low as about 10 ¹⁷ cm ^−3, which is about two orders of magnitude lower than when no AlN buffer layer is used, and the hole electron mobility at room temperature is 350 to 4
50 cm ² / V · s, which is about an order of magnitude larger.

Further, by further developing this method, a film grown by doping with Mg, which is an acceptor impurity, has a high resistance as it is, but becomes p-type by performing a low-acceleration electron beam irradiation treatment, and becomes a p-type film. It has been reported that resistance (several Ωcm) and light emission characteristics are improved (Japanese Journal
OF Applied Physics "Vol.28, L2112, 1989).

Recently, a small amount of In has been added to GaN by MBE or M
It has been reported that the crystallinity can be further improved by doping by the OVPE method (CK Shu et al., Appl. Phys.
tt., 73, 1998, 641 and F. Widmann et al., Appl.Phys.Let.
73.1998, 2642, Shen et al. `` Proceedings of the 59th Annual Meeting of the Japan Society of Applied Physics, '' 17pYB17,1998, Shen et al. 1999).

[0007]

As a material that enables high-density recording media and full-color devices, Group III nitrides are promising. However, in order to drive this device with electric current, a pn junction must be formed. It is essential to take. In the MOVPE method used for producing a p-type GaN layer in each layer constituting a short-wavelength laser diode, for example, trimethylgallium and ammonia are used as GaN raw materials, and an impurity raw material of a p-type conductivity control material is used. As biscyclopentadienyl magnesium (Cp
₂ Mg). Hydrogen was used as a carrier gas, the film growth temperature was around 1000 ° C.,
Then, a film in which GaN is doped is heat-treated to obtain a p-type low-resistance film.

However, in the conventional MOVPE method, GaN
, The p-type carrier concentration is at most 2 × 10 ¹⁸ cm ⁻³
In the case of GaInN, 5 × 10 ¹⁷ cm ⁻³
This is not sufficient in terms of increasing the efficiency of carrier injection and reducing the resistance. Therefore, now p-type G
It is particularly desirable to improve their properties by increasing the hole carrier concentration in the aN layer.

[0009]

The present inventor has previously found the following new method as a method for increasing the carrier concentration, and filed a patent application (Japanese Patent Application No. 10-288550).
issue).

That is, the invention of the earlier patent application is based on
Metalorganic compound vapor deposition on the buffer layer
At least a gallium source gas and a nitrogen source
GaN-based semiconductor using a gas containing p-type impurities and a gas containing p-type impurities
In the method of growing p, a gas containing p-type impurities is used.
Using a gas containing Mg, the carrier gas of these raw materials
Flow nitrogen gas substantially as well as an indium source
And the growth temperature is in the range of 800 to 1100 ° C.
And high-resistance Al with Mg inactivated_xGa _1-xyI
n_yN (0 ≦ x ≦ 1, 0 <y <0.3, x + y <1) film
Is formed, and this film is annealed to form a hole carrier.
P-type group III nitride characterized by increasing the concentration
This is a method for manufacturing a semiconductor.

According to the invention of the earlier patent application, GaN
About 7.0 × 10 ¹⁸ cm ⁻³ , GaInN, 1.0 × 1
A high hole carrier concentration as high as about 0 ¹⁸ cm ^-3 could be realized, and characteristics indicating high efficiency of the light emitting diode and low threshold of the laser diode were obtained. But,
Annealing had to be performed after film formation.

The present inventors continued further experimental research on the manufacturing method based on the invention of the above-mentioned prior patent application.
The half-width (FMHM) of the line rocking curve (XRC) depends on the TMI flow rate. If a small amount of In is doped, the film structure becomes different from that of Ga _1-x In _x N mixed crystal. Depending on the structure, crystallinity without annealing,
It has been found that the optical properties are improved.

That is, the present invention relates to a GaN compound semiconductor formed by metalorganic compound vapor deposition (MOVPE) on an AlN buffer layer provided on a sapphire substrate. It has an a-axis lattice constant and a c-axis lattice constant between the lattice constant value and the lattice constant value of bulk GaN (where the a-axis and c-axis substantially satisfy the strain-stress relationship of bulk BaN). A gallium nitride-based compound semiconductor comprising an In-doped GaN film.

The lattice constant of bulk GaN is, in principle, the lattice constant of unstrained GaN, and the reported values vary, but typical ones are 3.1892 A for the a-axis and 5.1850 A for the c-axis. It is. The lattice constants of the a-axis and the c-axis are correlated, and it is necessary to substantially satisfy the relationship between strain and stress of bulk GaN based on a well-known theoretical formula.

When a GaN film not doped with In is formed to a thickness of 2 μm using nitrogen gas as a carrier, the lattice constant of the a-axis is 3.1911 A and the lattice constant of the c-axis is 5.1.
830A. 2μm thickness using hydrogen gas as carrier
In this case, the lattice constant of the a-axis is 3.1841A and the lattice constant of the c-axis is 5.1883A. The value of this lattice constant tends to approach the lattice constant of bulk GaN as the film thickness increases.

According to the present invention, there is provided a sapphire substrate.
Metal organic chemical vapor deposition (MO) on the grown AlN buffer layer
(VPE) method.
Thus, the Al film formed by the MOVPE method_xGa_1-xN film
Of lattice constant and bulk Al _xGa_1-xN (however, 0
A-axis lattice constant between the value of the lattice constant of <x ≦ 1) and
c-axis lattice constant (however, a-axis and c-axis are bulk Al_xGa
_1-xN which substantially satisfies the relationship between strain and stress)
In-doped Al_xGa_1-xN (however, 0 <x ≦ 1)
Gallium nitride-based compound semiconductor
is there.

[0017] Bulk Al_xGa_1-xN (where 0 <x
The lattice constant of ≦ 1) is essentially a strain-free Al_xGa
_1-xN is a lattice constant of, for example, Al_0.15Ga_0.85N
The lattice constant of the a-axis of the film is 3.1774 A, and the lattice constant of the c-axis
Is 5.1542A. Lattice constants of a-axis and c-axis are correlated
Al based on well-known theoretical formula_0.15Ga
_0.85It is necessary to substantially satisfy the relationship between strain and stress of N
You.

3 μm in thickness using hydrogen gas as carrier gas
When the film is formed on the _substrate, Al _0.15 Ga _0.85
The lattice constant of the a-axis of the N film is 3.1824 A, and the lattice constant of the c-axis is 5.1792 A.

Further, the present invention relates to a method for growing a GaN compound semiconductor on a AlN buffer layer provided on a sapphire substrate by using a gas containing trimethylgallium and ammonia as a raw material gas by a metalorganic compound vapor deposition method. Nitrogen gas, hydrogen gas, or a mixed gas of nitrogen and hydrogen is flowed as a carrier gas for these raw materials, and the flow ratio of the carrier gas to the In gas source is 10 to 2
000, a growth temperature of 900 to 1150 ° C., and an In-doped GaN film is formed.

Further, according to the present invention, an AlN buffer layer provided on a sapphire substrate is formed on a AlN buffer layer using a gas containing trimethylgallium, trialkylaluminum, and ammonia as a source gas by a metalorganic compound vapor deposition method.
_In a method of growing a compound semiconductor of xGa ₁ -xN (where 0 <x ≦ 1), a nitrogen gas, a hydrogen gas, or a mixed gas of nitrogen and hydrogen is flowed as a carrier gas for these raw materials, A method for manufacturing a gallium nitride-based compound semiconductor, comprising forming an In-doped AlGaN film at a flow rate ratio of an In gas source of 10 to 20,000 and a growth temperature of 900 to 1200 ° C.

According to a new experiment conducted by the present inventors,
0.3-30 sl of nitrogen gas as carrier gas of raw material
m at a flow rate of 0.1 m, and trimethylindium is added at 0.1 m.
Flow at a flow rate of 01 to 20 μmol / min and a growth temperature of 9
When the temperature was set to 00 to 1150 ° C. and the GaN film was formed on the AlN buffer layer provided on the sapphire substrate, even though the crystal contained In by doping, a
It has been found that the lattice constant of the axis is small and the lattice constant of the c-axis is large, approaching the lattice constant of bulk GaN.

Also, when hydrogen gas is used as a carrier gas instead of nitrogen gas at 0.3 to 30 slm, the amount of nitrogen gas is increased as compared with the case of nitrogen gas and is flowed at a flow rate of 1 to 40 slm. 0.3-30 gas
Contrary to the case where slm was used, it was found that the lattice constant of the a-axis became large and the lattice constant of the c-axis became small, approaching the lattice constant of bulk GaN.

That is, a structure different from the mixed crystal is obtained.
Means that Usually Ga _1-xIn_xN
When the notation is used, it means a mixed crystal, and the base GaN
Shows that part of Ga in Group III has been replaced by In
are doing. Therefore, in this case, In atoms are better than Ga atoms.
Measures lattice constants because atoms have a larger atomic radius
Then, when In is included, both the a-axis and the c-axis become larger.

FIG. 1 shows the relationship between the lattice constants of the a-axis and the c-axis of In-doped GaN. Note that d is a film thickness.
■ (d = 3 μm), □ (d =
2 μm) is a film formed by substantially using a nitrogen gas as a carrier gas and setting the N ₂ / In ratio to 100 to 2000.
It shows the lattice constant of the n-doped GaN film, and it can be seen that the lattice constant is between the lattice constant of the GaN film not doped with In and the lattice constant of bulk GaN.

In the leftward region of FIG. 1, ● (d = 3 μm)
m) and （(d = 2 μm) are GaN films formed with a H ₂ / In ratio of 100 to 2000 using substantially hydrogen gas as a carrier gas. As shown in FIG. 1, in this case, the lattice constant of the In-doped GaN film is different from the lattice constant of the In-doped GaN film when nitrogen gas is used as a carrier gas, but is different from that of the GaN film without In-doping. It can be seen that the lattice constant is between the value of the lattice constant and the value of the lattice constant of bulk GaN. The arrow indicated by the thick line in FIG.
It shows the increasing direction of the MI flow rate, and shows that there is a correlation between the TMI flow rate and the lattice constant, and it approaches the lattice constant of bulk GaN as the TMI flow rate increases.

In general, in the case of Ga _1-x In _x N, as x increases, the lattice constants of the a-axis and the c-axis both become larger than those of bulk GaN. However, as shown in FIG. 1, as the TMI flow rate increases, the N ₂ / In ratio is increased to 1 using substantially nitrogen gas as a carrier gas.
In the GaN films formed with the thicknesses of 00 to 2000, the a-axis is indented and the c-axis is extended. On the other hand, the H ₂ / In ratio is set to 100
In the case of GaN having a film thickness of ２０００2000, the a-axis is extended, but the c-axis is steep.

The cause of such a difference between the case where a nitrogen gas carrier is used and the case where a hydrogen gas carrier is used is not clearly understood, but when a hydrogen carrier gas is used, the AlN buffer layer This is considered to be caused by the fact that the surface of the substrate is etched to change the thickness and surface state of the buffer layer.

In general, it can be seen that the values of the lattice constants of the a-axis and c-axis of bulk GaN are approaching. Therefore, this phenomenon cannot be explained by the idea that In is taken into GaN to form a mixed crystal.

Therefore, the present inventors have determined that this phenomenon is caused by "solid solution hardening". That is, In
Is not replaced by Ga, but is taken into the dislocation part in GaN, so that the movement of the dislocation is prevented, and the crystal becomes hard, which acts as an effect of suppressing the distortion of GaN, and has an effect on the lattice constant of bulk GaN. It is thought to be approaching.

If the lattice constant of the In-doped GaN film is between the value of the lattice constant of the GaN film formed by the MOVPE method and the value of the lattice constant of bulk GaN, The optical and electrical properties are greatly improved, and the dislocation density is from 1 × 10 ¹⁰ cm ⁻² to 5 × 1
To 0 ⁸ cm ^-2, if produced in a nitrogen carrier gas,
The luminous efficiency was increased up to 40 times at the maximum, and with respect to the electrical characteristics, the hole concentration of electrons due to residual impurities and defects was reduced from 7 × 10 ¹⁷ cm ⁻³ to 5 × 10 ¹⁶ cm ⁻³ .
In the case of manufacturing in a hydrogen carrier gas, the luminous efficiency is increased up to 10 times at the maximum, and the electron hole concentration is 1%.
× 10 ¹⁷ cm ^-3 has been reduced to 2 × 10 ¹⁶ cm ^-3 .

FIG. 2A shows the TMI flow rate (μmo) when nitrogen is used as a carrier gas and the growth temperature is 900 ° C.
1 / min) and the crystal mosaic property (so-called tilt) in the c-axis direction of the GaN film. FIG. 2B shows Ga
Crystal mosaicity in the a-axis direction of the N film (so-called twist)
The relationship is shown below. In order to dope In into the GaN film,
As the MI flow rate is increased, the half width becomes narrower, that is, the structure is improved. The preferred TMI flow rate was 0.01-20 μmol / min when using a nitrogen carrier.

The In-doped GaN film of the present invention shows p-type even without annealing, that is, as grown. Furthermore, the method for producing a gallium nitride-based compound semiconductor of the present invention is applied to ordinary GaN or AlGaN, regardless of the p-type, to improve the crystallinity by reducing the dislocation density by In doping, and to improve the optical characteristics. Improved, LED
Luminous efficiency is increased by about 30%, and a remarkable characteristic that the oscillation threshold value of the laser diode is reduced to 1/5 is provided. Further, it has also become possible to suppress the generation of cracks, which has conventionally been a problem when forming AlGaN on GaN. The cause of the effect of such improvement can be explained by the effect of “solid solution hardening” described above.

The gallium nitride-based compound semiconductor of the present invention comprises:
Single layer film and GaN / AlGaN, AlGaN / AlG
A similar effect was observed in the well layer and / or barrier layer having the aN multiple quantum well structure. FIG. 3 shows a structure in which the present invention is applied to a laser diode. As a combination for doping In, three types of a p layer, an n layer, and an active layer can be considered. Whichever layer is used, the lasing threshold of the laser decreases and the emission intensity increases.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the production method of the present invention, a conventionally known apparatus for growing GaN on sapphire of a substrate using a horizontal reaction tube can be used. For example, the substrate holder to be induction-heated is placed in a horizontal tubular reaction tube, the sapphire substrate is held diagonally in the holder, and the reaction gas flows into the reaction tube together with the carrier gas at normal pressure from the introduction port into the reaction tube. After the decomposition and the deposition of the compound semiconductor film on the substrate, the reaction gas is discharged from the vacuum exhaust port. On the sapphire substrate, an AlN layer is provided as a buffer layer at a low temperature by a known means.

As a raw material of GaN, trimethylgallium (TMG) and ammonia (NH ₃ ) are suitable. I
As the n source, trimethyl indium (TMI), triethyl indium (TEI), indium trisacetylacenate, indium trisdipivaloyl methanate, indium trishexafluoroacetylacenate, or the like can be used.

The carrier gas has a flow rate ratio N with respect to the In source.
₂ / In, H ₂ / In, (N ₂ 5 to 95% by volume + H ₂ )
/ In is set to 10 to 20,000. The growth temperature is GaN
900-1150 ° C for film, 90 for AlGaN film
The temperature is preferably from 0 to 1200 ° C, and from the viewpoint of crystallinity, the most preferable range is from 950 to 1050 ° C.

Gas containing Mg as a gas containing p-type impurities
When using magnesium, biscyclopen
Tadienyl magnesium (Cp_TwoMg), methyl bis
Clopentadienyl magnesium (C₆H₇)_TwoMg,
(CH_ThreeC_FiveH_Four)_TwoMg, (C_FiveH_FiveC_FiveH_Four)_TwoM
g, (i-C_ThreeH₇C_FiveH_Four)_TwoMg, (n-C_ThreeH ₇
C_FiveH_Four)_TwoMg or the like may be used. Mg to be doped
Is 1 × 10¹⁹cm^-3More than required, Mg concentration
Is proportional to the flow rate of the gas containing Mg in a certain flow rate range.
For example, the flow rate of the gas is adjusted to an appropriate range.

In the case of forming an AlGaN film by adding an Al source, a trialkylaluminum such as trimethylaluminum (TMAl) or triethylaluminum (TEAl) is suitable as a raw material of Al.

To summarize the above, specific conditions are as follows:
TMGa: 2.5 to 25 μmol / min, ammonia:
0.02 to 0.2 mol / min, TMI: 0.01 to 20
μmol / min (≦ 500 sccm), nitrogen as a carrier gas: 0.3 to 30 slm, or hydrogen gas: 1 to 1
40 slm or hydrogen gas + nitrogen gas: 1 to 40 sl
m, the growth temperature is 900 to 1200 ° C., the growth pressure is 70 to 760 Torr, and the thickness is 100 to 200.
A 0 nm GaN layer is grown.

When an Mg source is added, biscyclopentadienyl magnesium (Cp ₂ Mg): 0.0
1 to 0.5 μmol / min. When adding TMAl, T
MAl: 30 to 300 μmol / min is preferred.

The molar ratio of the In source gas supplied as a source gas during the growth was 0.00
It is adjusted to 1 or more, more preferably 0.01 or more, and still more preferably 1.0 or more. If it is less than 0.1, the crystallinity will be poor. It is preferable to increase the molar ratio of the In source gas as the growth temperature increases, and accordingly the crystallinity improves.

To form GaN by the MOVPE method, ammonia is usually used as a reaction gas of a nitrogen source.
In this case, in order to deposit a compound semiconductor having few crystal defects on a substrate at a practical rate, an ammonia flow rate of 500,000 times that of an alkyl compound of a group III element is required, and a high growth rate of 1000 to 1200 ° C. is usually required. It is desirable to increase the utilization efficiency of ammonia as the temperature. The present invention can be grown at a high temperature close to this temperature, has the effect of increasing the efficiency of ammonia utilization, and significantly improving productivity.

[0043]

Example 1 An atmospheric pressure MOVPE method using a horizontal reaction tube was carried out under the following conditions. A sapphire (0001) plane was used as the substrate.
After hydrogen baking at 10 ° C. for 10 minutes, an AlN buffer layer of about 50 nm was deposited at a growth temperature of 600 ° C. for a growth time of 5 minutes. The flow rate of the raw material is TMA: 5 sc
cm, NH ₃ : 1slm, N ₂ as carrier gas:
The total amount was 3 slm.

Subsequently, two GaN layers of about 2 μm and 3 μm were deposited at a growth temperature of about 1000 ° C. and a growth time of about 20 minutes. The flow rate is TMG: 10 sccm, NH ₃ : 1
_{slm, Cp 2 Mg: 20sccm,} TMI: 0.4~
8.0 μmol / min, N ₂ as carrier gas:
The test was performed at 5 slm and a total amount of 10 slm. For comparison, a film was also formed when the TMI flow rate was set to 0.

Example 2 GaN was used under the same conditions as in Example 1 except that H ₂ gas was used at the same flow rate instead of N ₂ gas as the carrier gas.
Layers were deposited in duplicate, about 2 μm and 3 μm. TM of In-doped GaN obtained by Examples 1 and 2
FIG. 4 shows the relationship between the I flow rate (μmol / min) and the crystal mosaic property (so-called tilt) in the c-axis direction. Similarly, FIG. 5 shows the crystal mosaic property (so-called twist) in the a-axis direction. FIG. 5 shows the results suggesting a decrease in the density of edge dislocations and screw dislocations. Table 1 (Example 1) and Table 2 (Example 2) below show the relationship between the TMI flow rate and the lattice constant. In Example 2, although the crystallinity was inferior to Example 1, there was a correlation between the TMI flow rate and the crystallinity.
It can be seen that the crystallinity can be improved by increasing the I flow rate.

[0046]

[Table 1]

[0047]

[Table 2]

FIG. 6 shows the results of surface observation of In-doped GaN using an atomic force microscope (AFM). FIG. 6 (a)
(B) shows the case of a GaN film which is not doped with In and doped with TMI, and (b) shows that the TMI is 1.6 μm.
In this case, GaN was doped with In at a flow rate of ol / min. It can be seen that the surface condition was very good.

Example 3 TMA: 20 sccm was added, and hydrogen gas was used as a carrier.
3 μm AlGaN under the same conditions as in Example 1 except for
A film was formed. Mg concentration 2 × 10¹⁹cm^-3, Hole carry
A concentration 1.0 × 10¹⁸cm^-3, Mobility 0.1cm^Two/ V
S p-type Al _0.15Ga_0.85An N film was obtained.

FIG. 7 shows Al _0.15 Ga doped with In.
Crystal _{mosaicity in} the c-axis direction of _0.85 N (so-called tilt)
Is shown. Table 3 below shows the relationship between the TMI flow rate and the lattice constant.

[0051]

[Table 3]

[0052]

According to the present invention, the crystallinity of a gallium nitride based semiconductor is improved, the hole concentration based on residual impurities and defects is reduced, and the optical characteristics are improved. This has a great effect on lowering the threshold value of the diode.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the a-axis lattice constant, the c-axis lattice constant, and the TMI flow rate of In-doped GaN.

FIG. 2 (a) shows TMI flow rate (μmol / min) and c
5 is a graph showing a relationship with crystal mosaicity (so-called tilt) in the axial direction. (B) is a graph showing the relationship between the TMI flow rate (μmol / min) and the crystal mosaicity in the a-axis direction (so-called twist).

FIG. 3 is a schematic view showing a structure in which the manufacturing method of the present invention is applied to a laser diode.

FIG. 4 is a graph showing the relationship between the TMI flow rate (μmol / min) of In-doped GaN obtained in Example 1 and Example 2 and crystal mosaicity (so-called tilt) in the c-axis direction.

FIG. 5 is a graph showing the relationship between the TMI flow rate (μmol / min) of In-doped GaN obtained in Example 1 and Example 2 and crystal mosaicity in the a-axis direction (so-called twist).

FIG. 6 (a) shows GaN without adding TMI to the source gas and not doped with In, and FIG. 6 (b) shows TMI of 0.4 μm
A drawing substitute photograph showing the surface observation result of an In-doped GaN flowing at ol / min using an atomic force microscope (AFM).

FIG. 7 is a graph showing crystal mosaicity (so-called tilt) in the c-axis direction of In-doped Al _0.15 Ga _0.85 N.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5F041 AA03 AA40 CA05 CA34 CA40 CA46 CA49 CA57 CA65 FF01 FF16 5F045 AA04 AB14 AB17 AB18 AC08 AC12 AC15 AC19 AD13 AD14 AD15 AF09 BB12 BB16 CA11 DA53 HA06

Claims (4)

[Claims] 1. A lattice constant of a GaN compound semiconductor formed by a metalorganic compound vapor deposition (MOVPE) method on an AlN buffer layer provided on a sapphire substrate, wherein the GaN film is formed by the MOVPE method. And bulk GaN
Consisting of an In-doped GaN film having an a-axis lattice constant and a c-axis lattice constant between the lattice constants (where the a-axis and c-axis substantially satisfy the relationship between strain and stress of bulk GaN). A gallium nitride-based compound semiconductor, comprising: 2. An AlN buffer provided on a sapphire substrate.
Metal organic compound vapor phase epitaxy (MOVPE)
AlGaN compound semiconductor formed by MOVP
Al deposited by E method_xGa_1-xValue of lattice constant of N film
And bulk Al _xGa_1-xCase of N (however, 0 <x ≦ 1)
A-axis lattice constant and c-axis lattice constant between the values of the child constants
(However, a-axis and c-axis are bulk Al_xGa_1-xN distortion
Which substantially satisfies the relationship between
l_xGa_1-xN (where 0 <x ≦ 1)
A gallium nitride-based compound semiconductor. 3. A method of growing a GaN compound semiconductor on a AlN buffer layer provided on a sapphire substrate by a metal organic compound vapor deposition method using an organic metal containing Ga and a gas containing ammonia as a source gas. Nitrogen gas, hydrogen gas,
2. The method according to claim 1, wherein a mixed gas of nitrogen and hydrogen is supplied, a flow ratio of a carrier gas to an In gas source is 10 to 20,000, a growth temperature is 900 to 1150 ° C., and an In-doped GaN film is formed. A method for producing a gallium nitride-based compound semiconductor. 4. An Al _x Ga layer is formed on an AlN buffer layer provided on a sapphire substrate by a metal organic compound vapor phase epitaxy using an organic metal containing Ga, an organic metal containing Al, and a gas containing ammonia as a source gas. _In a method for growing a _1-xN (where 0 <x ≦ 1) compound semiconductor, a nitrogen gas, a hydrogen gas, or a mixed gas of a nitrogen gas and a hydrogen gas is flowed as a carrier gas for these materials, and a carrier gas and an In gas are mixed. Gas source flow ratio 10-200
3. The method of manufacturing a gallium nitride-based compound semiconductor according to claim 2, wherein the growth temperature is 900 to 1200 ° C., and an In-doped AlGaN film is formed.