JP2003110141A - Method for manufacturing gallium nitride-based compound semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method exhibiting high manufacture efficiency by which low-resistance p-type aluminum gallium indium nitride can be formed in the state of as-grown without annealing an AlGaN film doped with p-type impurities. SOLUTION: Aluminum gallium indium nitride doped with p-type impurities is grown from organic metal materials in the presence of indium organic metal materials in the temperature range of 950 to 1,100 by an organic metal vapor phase growth method. After that, a high-resistance aluminum gallium indium nitride layer doped with p-type impurities is grown in the temperature range of 950 to 750 on the aluminum gallium indium nitride and is cooled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a gallium nitride-based compound semiconductor used for a purple, blue or green light emitting diode, a purple or blue laser diode, etc., and particularly to a method of annealing after vapor phase growth. The present invention relates to a method of obtaining a p-type aluminum gallium indium nitride compound semiconductor, which is unnecessary and has excellent manufacturing efficiency.

[0002]

2. Description of the Related Art As a method for producing a p-type gallium nitride-based compound semiconductor, a gallium nitride-based compound semiconductor is grown by metalorganic chemical vapor deposition (MOCVD) after being doped with Mg as an acceptor impurity. A method is known in which the resistance is reduced by heating at 400 ° C. or higher in an inert atmosphere such as nitrogen and performing thermal annealing (see Japanese Patent Laid-Open No. 5-183189). However, in the thermal annealing treatment, after the vapor phase growth is completed, it is necessary to replace the atmospheric gas, heat it again to a high temperature and hold it, and there is a problem that the manufacturing efficiency is inferior. There is also known a method of obtaining a p-type aluminum gallium indium nitride indium compound semiconductor having a low resistance after MOCVD growth, instead of using the p-type aluminum gallium indium nitride compound semiconductor having a low resistance by an additional step after the crystal growth as described above. Has been. For example, p such as Mg
At the time of cooling after vapor phase growth of a gallium nitride-based compound semiconductor doped with a type impurity, the atmosphere containing a hydrogenating gas is switched to an atmosphere of hydrogen or nitrogen at a temperature of 400 ° C. or higher,
Method for obtaining a p-type gallium nitride compound semiconductor having low resistance without heat treatment without causing hydrogen passivation (see Japanese Patent Application Laid-Open No. 8-115880), in which substantially nitrogen gas is used as a carrier gas, and a gas of an indium source is used as a raw material source. There is known a manufacturing method (see Japanese Patent Application Laid-Open No. 2001-94149) for obtaining a p-type group III nitride semiconductor by flowing the same into the growth apparatus at the same time. However, hydrogen as a carrier gas remaining in the device, hydrogen based on a hydrogenated gas, or the like diffuses in the film of the gallium nitride-based compound semiconductor during cooling, which makes it difficult to obtain a high hole carrier concentration and also has good reproducibility. There is a problem in manufacturing efficiency such as not being present. In order to avoid this, a gallium nitride-based compound semiconductor layer doped with p-type impurities is grown, and then cooled while the n-type gallium nitride-based compound semiconductor layer is grown on the gallium nitride-based compound semiconductor layer, so that hydrogen atoms and the like are removed. There is known a method for preventing the intrusion into the type semiconductor layer (see Japanese Patent Laid-Open No. 8-8460). However, it is necessary to remove the n-type gallium nitride-based compound semiconductor layer after the growth by reactive ion etching (RIE) method or the like, which makes the process complicated and the manufacturing efficiency is not good.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a highly efficient method for producing a low-resistance p-type aluminum gallium indium compound semiconductor without thermal annealing treatment.

[0004]

In order to solve the above-mentioned problems, the present invention is a metal-organic vapor phase epitaxy method in a temperature range of 950 ° C. to 1100 ° C. in an atmosphere containing hydrogen as a main component, in the presence of indium metal organic source, while doping a p-type impurity, aluminum and gallium organometal starting material, p-type first aluminum gallium nitride indium film _{(Al y Ga x in l-} x-y N, However, 0
<X ≦ 1, 0 ≦ y <1, 0 <1-x-y <1) is grown, and M of high concentration is further grown in a temperature range of 950 ° C. to 750 ° C.
g second aluminum gallium nitride indium film of high resistivity doped _{(Al a Ga b In l-} a-b N, however, 0 ≦ a <1,0 <b ≦ 1,0 <1-a-b <1)
Is a method of growing thinly and then cooling in a nitrogen atmosphere. Here, “in the presence of an In metal organic material” means Al, Ga for growing aluminum gallium indium nitride.
That is, the organometallic raw material containing In is allowed to flow in the film formation reaction device together with the organometallic raw material described in (1) above, and high-resistivity aluminum gallium indium nitride is annealed in a nitrogen gas atmosphere at 750 ° C. for 30 minutes and then subjected to hole measurement. , A film showing a high resistance of 10 ⁶ Ω · cm or more, and in a state where n-type or p-type determination cannot be performed. When GaN is grown by MOCVD in an atmosphere of hydrogen or the like in the presence of an indium organometallic raw material, GaN with good crystallinity is obtained, which is known as an isoelectronic effect (Applied Physics Lctters,
Vol. 73, 641, 1998). When p-type aluminum gallium indium nitride is grown while doping a p-type impurity under this condition, Mg has a good crystallinity, so that Mg is accurately substituted at the Ga position and Mg is inactivated by hydrogen. Aluminum gallium indium nitride films with few and high hole carrier concentrations are expected. Although the reason why the low-resistance p-type first aluminum gallium indium nitride film is formed by the high-resistance second aluminum gallium indium nitride film is not clear, the bonding surface between the first film and the second film, Alternatively, it is considered that the second film functions as some kind of barrier to prevent hydrogen from diffusing and penetrating into the first p-type aluminum gallium indium nitride film.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is based on the MOCVD method.
By growing the first and second high-resistance aluminum gallium indium nitride films from the organic metal raw materials of Al and Ga in the presence of the n-organic metal raw material, the low-resistance first p-type that does not require annealing treatment. That is, an aluminum gallium indium nitride film can be formed. That is, as
Forming a p-type aluminum gallium indium nitride film in the -grown state.

The film is formed on the sapphire substrate by the MOCVD method, that is, the temperature range for growing the first aluminum gallium indium nitride film is 900 ° C. to 1150 ° C. The temperature is preferably 950 ° C. or higher, which facilitates two-dimensional growth. Further, at 1150 ° C. or higher, the decomposition of aluminum gallium indium nitride is severe and the active layer is deteriorated. Preferably 95
The temperature is from 0 ° C to 1050 ° C. The first aluminum gallium indium nitride film is formed of Al and Ga in the presence of In organometallic raw material in an atmosphere containing a carrier gas such as hydrogen as a main component.
While doping p-type impurities from the organic metal raw material of
Grow at a growth rate of μ / Hr to 2 μ / Hr. In the above temperature range, In is hardly taken into the crystal and X
The line diffraction results show the pattern of aluminum gallium nitride. According to SIMS analysis, the In / Ga content ratio of the crystal film is 0.
It is about 1% or less, which is considered to be a state in which In is solid-dissolved unlike the mixed crystal. Therefore, after growing the first aluminum gallium indium nitride film at a constant temperature of 1050 ° C., a thin film may be grown at a low growth rate while flowing the In organometallic raw material up to about 950 ° C. in the cooling process. It may be grown while cooling from ℃ to 950 ℃. If the ratio of the In source gas to the Ga source gas is small, the crystallinity of the aluminum gallium indium nitride film is difficult to improve, and if it is too large, the crystallinity deteriorates. Therefore, the ratio of the In source gas to the Ga source gas is 1% to 40%. %, 5
% To 20% is preferred. The ratio of p-type impurity source gas such as Mg to Ga source gas is 0.01% to 1%.
Therefore, the range of 0.05% to 0.8% is preferable.

After the growth of the first p-type aluminum gallium indium nitride film, the carrier gas containing hydrogen as the main component is switched to the carrier gas containing nitrogen as the main component, and the temperature is 950 ° C.
To 750 ° C., a second aluminum gallium indium nitride film is grown in a solid solution state of In or a mixed crystal state containing In while doping p-type impurities. Nitrogen gas is used as the main carrier gas, and hydrogen gas is used as the carrier gas for the organometallic raw material gas.
The hydrogen concentration in the reaction section of the device is from 1% by volume to 1
It is preferably in the range of 0% by volume. Since the crystallinity deteriorates at 750 ° C or lower, a temperature range of 950 ° C to 750 ° C is preferable. The ratio of the In source gas to the Ga source gas is the same as the growth condition of the first p-type aluminum gallium indium nitride film, but when the light emitting diode (LED) is formed, the second aluminum gallium indium nitride film is removed from the active layer. It is preferable not to serve as a light absorbing layer. In the case of a blue LED having a peak wavelength of 450 nm, the In content is 10% or less, preferably 5% or less. The ratio of the p-type impurity source gas such as Mg to the Ga source gas is the same as that of the growth condition of the first p-type aluminum gallium indium nitride film, but when the carrier gas is substantially nitrogen gas, the p-type impurity gas such as Mg Since the amount of the type impurities taken into the film increases, the resistance tends to be high. When the ratio of In source gas to Ga source gas is constant, the In ratio in the film increases as the growth temperature decreases. Therefore, the growth may be performed at a constant temperature or 95 while controlling the amounts of In and Mg.
It may be during the cooling process from 0 ° C to 750 ° C. In general, nitrogen gas has a smaller amount of oxygen and the like than hydrogen gas and is not good in purity, but since it maintains and promotes activation of Mg, it is used in the cooling process after the second aluminum gallium indium nitride film is formed. Nitrogen containing oxygen up to about 10 ppm or less, preferably about 1 ppm or less, which does not excessively oxidize the surface of the film, may be flowed. When manufacturing a light emitting diode or the like, the thickness of the second aluminum gallium indium nitride is high resistance, so that the film thickness is preferably 50 nm or less, 5 nm to 20 nm. Current flows in this film in the film thickness direction and does not show a large resistance. Although the mechanism is unknown, a mechanism different from the conventional one, for example, a hopping or tunnel-like mechanism that intervenes a defect,
The work function near the pit may be low and the contact potential may be low. Therefore, the second aluminum gallium indium nitride does not need to be removed by the RIE method or the like when the LED device is manufactured, and the manufacturing efficiency is high.

Raw materials are trimethylgallium (hereinafter referred to as TMG), trialkylgallium such as triethylgallium, trimethylaluminum (hereinafter referred to as TMA),
Trialkylaluminum such as triethylaluminum, trimethylindium (hereinafter referred to as TMI), or the like is used. As the p-type impurity, a compound having an organic group such as an alkyl group in Mg, Zn, Be or the like, or a chelate compound is used, but in terms of activation efficiency, biscyclopentadienyl magnesium (hereinafter referred to as Cp ₂ Mg) and bis. Organic Mg compounds such as ethylcyclopentadienyl magnesium are preferred.

When the LED film is deposited by this new p-type conversion method, the low temperature buffer layer is not limited to the GaN film, and
1N film and AlGaN film, undoped GaN film is AlG
An aN film or a GaN film that is lightly doped with Mg may be used, and a Si-doped GaN film may be an Si-doped AlGaN film.

[0010]

Example 1 A smooth sapphire substrate having a plane orientation of 0.2 degrees from the c-plane and a thickness of about 300 μm is treated in a mixed acid (sulfuric acid: phosphoric acid = 3: 1) heated at 110 ° C. for 30 minutes. Then
Substrate treatment was performed by washing well with pure water and drying.

The sapphire substrate was placed on a substrate holder inside a horizontal MOCVD apparatus, and the temperature was set to 1100 ° C. in a hydrogen atmosphere.
The substrate was held at the high temperature for 5 minutes to perform high temperature cleaning of the substrate.

Next, the temperature is lowered to 500 ° C., hydrogen as a main carrier gas is 6 liters / minute, and ammonia is 3.5
The carrier gas for TMG was flowed at 10 cc / min for 5 minutes while flowing at liter / min to form a GaN low temperature buffer layer having a thickness of about 20 nm.

Then, only TMG is stopped and the temperature is raised to 1050.
The temperature is increased to ℃, and hydrogen (8 liters / minute) and ammonia (3.5 liters / minute) are used as the main carrier gas.
A carrier gas for MG was flowed at 40 cc / min and held for 60 minutes to obtain an undoped GaN film having a thickness of 1.5 μm.

Next, the temperature is lowered to 1000 ° C., hydrogen gas as a main carrier gas is 8 liters / minute, ammonia is 3.5 liters / minute, and carrier gas for TMG is 40 c.
While flowing at c / min, TMI as an In source gas is 10% with respect to the Ga source gas 1 and Cp ₂ Mg as an Mg source gas is 0.2% with respect to the Ga source gas 1 and 10%.
The first minute gallium indium nitride was prepared by holding the amount. Then, TMG, TMI, and Cp ₂ Mg were stopped, the main carrier gas was switched from hydrogen gas to nitrogen gas, and flowed at 8 liters / minute, while flowing ammonia at 3.5 liters / minute, cooling rate was 10 ° C. / The temperature was set to 900 ° C. in about a minute. 9
A carrier gas for TMG was flown again at 00 ° C. at 10 cc / min, TMI as an In source gas was 10% with respect to the Ga source gas 1, and Cp ₂ Mg as an Mg source gas was 0.6 with respect to the Ga source gas 1. Flow for 10% and hold for 2 minutes
Was prepared. After forming the film, it was naturally cooled to room temperature while flowing only nitrogen gas.

After cooling, the substrate with the film was taken out from the MOCVD apparatus, and hole measurement was performed, which showed high resistance.
When this high resistance layer is removed by the RIE method and hole measurement is performed, it shows a p-type and has a carrier concentration of about 9 × 10 ¹⁷ / cm 3.
^{3. The} resistivity was about 1 Ω · cm. MOCVD
The wafer taken out from the apparatus was annealed in a nitrogen gas atmosphere at 750 ° C. for 30 minutes, and the hole measurement was performed.

[0016]

Example 2 The same method as in Example 1 except that when the second gallium indium nitride film was formed, Cp ₂ Mg as a Mg source gas was flowed so as to be 0.3% with respect to the Ga source gas 1. It was formed into a film. After cooling, the substrate with the film was taken out from the MOCVD apparatus, and hole measurement was performed, which showed high resistance. When this high resistance layer is removed by the RIE method and hole measurement is performed, it shows a p-type and the carrier concentration is about 7 × 10 ¹⁷ / c.
m ³ , and the resistivity was about 1 Ω · cm. MOCV
The wafer taken out from the D device was annealed at 750 ° C. for 30 minutes in a nitrogen gas atmosphere, and the hole measurement was performed.

[0017]

Example 3 Substrate processing, substrate high temperature cleaning, low temperature buffer layer formation, undoped GaN film formation, and first gallium indium nitride film formation were carried out in the same manner as described in Example 1. After that, TMG, TMI, C
Stopping p ₂ Mg, switching the main carrier gas from hydrogen gas to nitrogen gas, flowing at 8 liters / minute, and flowing ammonia at 3.5 liters / minute, cooling rate 10 ° C. /
The temperature was raised to 850 ° C in about a minute. At 850 ° C., 10 cc / min of TMG carrier gas is not flowed again, but Cp ₂ Mg is used as the Mg source gas for the dopant so that TMI is 5% with respect to the Ga source gas 1 as the In source gas. A second gallium indium nitride film was formed by flowing the source gas so as to be 0.6% and holding it for 10 minutes. After the film formation, the temperature was naturally cooled to 850 ° C. or lower while flowing nitrogen gas as it was. After cooling, the substrate with the film was taken out from the MOCVD apparatus, and hole measurement was performed, which showed high resistance. When this high resistance layer is removed by the RIE method and hole measurement is performed, it shows a p-type and has a carrier concentration of about 1 × 10 ¹⁸ / c.
m ³ , and the resistivity was about 1 Ω · cm. MOCV
The substrate with the film taken out from the device D was annealed at 750 ° C. for 30 minutes in a nitrogen gas atmosphere, and the hole measurement was performed. As a result, the resistance was high.

[0018]

Example 4 Substrate treatment, substrate high temperature cleaning, low temperature buffer layer formation, and undoped GaN film formation were performed in the same manner as described in Example 1. Then 10
While cooling from 50 ° C. to 950 ° C. at about 10 ° C./min, hydrogen gas as a main carrier gas was 8 liters / min,
Ammonia of 3.5 liters / minute and carrier gas of TMG at 40 cc / minute were flown so that TMI as an In source gas was 10% with respect to Ga source gas 1 and Cp ₂ was used as a Mg source gas for a dopant. Mg was made to flow to Ga source gas 1 so that it might become 0.15%, and the 1st gallium indium nitride film was created. After that, the main carrier gas was switched from hydrogen gas to nitrogen gas, and the carrier gas for TMG was flowed at 10 cc / min while cooling from 950 ° C. to 850 ° C. at about 10 ° C./min.
To 5% relative to the Ga source gas 1 and Cp ₂ Mg as the Mg source gas as a dopant to 0.5% relative to the Ga source gas 1 to form a second gallium indium nitride film. It was created. After forming the film, it was naturally cooled to room temperature while flowing nitrogen gas as it was. After cooling, MOCVD
When the substrate with the film was taken out from the device and hole measurement was performed, it showed high resistance. When this high-resistance layer was removed by the RIE method and hole measurement was performed, it showed a p-type, a carrier concentration of about 8 × 10 ¹⁷ / cm ³ , and a resistivity of about 1 Ω · cm. The substrate with the film taken out from the MOCVD apparatus was annealed at 750 ° C. for 30 minutes in a nitrogen gas atmosphere, and the hole was measured to find that it had a high resistance.

[0019]

[Embodiment 5] TMA is used as the film forming condition for the first film of Embodiment 3.
At a rate of 10 cc / min to form a first aluminum gallium indium nitride film, and the second film of Example 3 was formed under the same conditions as TMA at a rate of 2 cc / min. An aluminum gallium indium nitride film was created. After cooling, the substrate with the film was taken out from the MOCVD apparatus, and hole measurement was performed, which showed high resistance. When this high-resistance layer was removed by the RIE method and hole measurement was performed, it showed a p-type, carrier concentration was about 3 × 10 ¹⁷ / cm ² , and resistivity was about 2.5 Ω · cm. The substrate with the film taken out from the MOCVD apparatus was annealed at 750 ° C. for 30 minutes in a nitrogen gas atmosphere, and the hole was measured to find that it had a high resistance.

[0020]

Example 6 Substrate treatment, substrate cleaning, low temperature buffer layer formation, and undoped GaN film formation were carried out in the same manner as described in Example 1. The undoped Ga
The following film was formed on the N film. Hydrogen gas as main carrier gas is 8 liters / minute, ammonia is 35 liters / minute
, TGC carrier gas at 40 cc / min, and hydrogen-diluted 100 ppm monosilane at 2.5 cc / min for 60 minutes while flowing to obtain Si having a thickness of 1.5 μm.
A doped GaN film was obtained. Then, at 760 ° C., a Si-doped GaN barrier layer having a thickness of 7 nm and a thickness of 3 nm are formed in a nitrogen atmosphere.
An MQW composed of 5 pairs of quantum well layers of nm undoped Ga _0.7 In _0.3 N well layer was sequentially stacked with the barrier layer, the well layer, and finally the barrier layer was stacked. After that, 1000 ℃
Unheated Al with a thickness of 10 nm to prevent Mg diffusion and block electron carriers in a hydrogen atmosphere.
_0.1 Ga _0.9 N was laminated. Then, as main carrier gas, hydrogen gas was 8 liters / minute, and ammonia was 3.
5 liters / minute, carrier gas for TMG 40 cc /
Flowing in minutes, TMI as In source gas is 10% with respect to Ga source gas 1 and Cp ₂ Mg as Mg source gas is Ga.
The first gallium indium nitride film was formed by allowing the source gas to flow at 0.2% and holding it for 10 minutes. Then, stop TMG, TMI, and Cp ₂ Mg, and switch the main carrier gas from hydrogen gas to nitrogen gas 8 liters /
Minute, while flowing ammonia at 3.5 liters / minute, the cooling rate was set to 850 ° C. at about 15 ° C./minute. At 850 ° C., a carrier gas for TMG was flown again at 10 cc / min to remove In
As source gas, TMI is 10% with respect to Ga source gas 1, M
As a g source gas, Cp ₂ Mg was added to Ga source gas 1 in an amount of 0.1
A second gallium indium nitride film was formed by pouring the solution to 6% and holding it for 4 minutes. After forming the film, it was naturally cooled to room temperature while flowing only nitrogen gas. The surface of the sapphire substrate opposite to the side on which the GaN-based semiconductor was deposited was polished to a thickness of about 100 μm. Next, the second with high resistance
A part of the gallium indium nitride film was removed by RIE from the surface to a depth reaching the Si-doped GaN layer. Then, Al, C are formed on the exposed surface of the Si-doped GaN layer.
A thin film of r, Al, and Au is sequentially formed, and then 550 in a nitrogen atmosphere.
Annealed at 5 ° C for 5 minutes to form an n-electrode. The second
On the surface of the Mg-doped high-resistance gallium indium nitride layer of
Thin films of i and Au were sequentially formed and annealed in air at 550 ° C. for 10 minutes to form a p electrode. Next, connect the gold wire to each electrode and mold with resin according to the usual method to LE.
D. When it was made to emit light at a forward voltage of 20 mA, it showed blue light emission of Vf3.5V and a wavelength of 450 nm.
The emission output was 3 mW, which was a very good characteristic.

[0021]

[Embodiment 7] Undoped Al _0.1 having a thickness of 10 nm laminated to prevent Mg diffusion or block electron carriers.
The layers up to the Ga _0.9 N layer were formed by the same method as in Example 5. First and second gallium indium nitride films were formed on the Al _0.1 Ga _0.9 N layer as follows. 1
While cooling from 050 ° C. to 950 ° C. at about 10 ° C./min, hydrogen gas as a main carrier gas was 8 liters / min,
Ammonia was flowed at 3.5 liters / minute, TMG carrier gas was flowed at 40 cc / minute, and TMI as In source gas was 10% with respect to Ga source gas 1 so that Cp ₂ was used as a dopant and Mg source gas. Mg was made to flow to Ga source gas 1 so that it might become 0.15%, and the 1st gallium indium nitride film was created. After that, the main carrier gas was switched from hydrogen gas to nitrogen gas, and the temperature was changed from 950 ° C to 850 ° C.
Carrier gas for TMG is flowed at 4 cc / min while cooling to 10 ° C./min at about 10 ° C./min, and TMI is used as an In source gas at G
a. As a dopant, Cp ₂ Mg as a Mg source gas was flowed so as to be 5% with respect to the a source gas 1 so as to be 0.5% with respect to the Ga source gas 1, and the second gallium indium nitride film was formed. Formed. After forming the film, it was naturally cooled to room temperature while flowing nitrogen gas as it was. After forming the film, an LED was prepared in the same manner as in Example 5 and the characteristics were evaluated. When light was emitted at a forward voltage of 20 mA, Vf3.6V,
It emits blue light with a wavelength of 450 nm and the emission output is 2.8 m.
It showed a very good characteristic of W.

[0022]

COMPARATIVE EXAMPLE 1 Substrate treatment, substrate high temperature cleaning, low temperature buffer layer formation, and undoped GaN film formation were carried out in the same manner as described in Example 1. Then set the temperature to 1
The temperature was lowered to 000 ° C., and hydrogen gas was 8 liters / minute, ammonia was 3.5 liters / minute, and carrier gas for TMG was 40 c as main carrier gas on the undoped GaN film.
Cp ₂ Mg as a Mg source gas while flowing at c / min
The a source gas was flowed at 0.2% with respect to 1 and held for 10 minutes to form a GaN film. After that, TMG, Cp ₂ M
g, and the main carrier gas was changed from hydrogen gas to nitrogen gas, while flowing 8 liters / minute and ammonia at 3.5 liters / minute, while cooling at a rate of about 10 ° C./minute to 850
C., and 850.degree. C. or lower was naturally cooled to room temperature in a nitrogen atmosphere. After cooling, the substrate with the film was taken out from the MOCVD apparatus, and hole measurement was performed, which showed high resistance. The substrate with the film taken out from the MOCVD apparatus was annealed at 750 ° C. for 30 minutes in a nitrogen gas atmosphere, and hole measurement was performed to show a p-type.

[0023]

COMPARATIVE EXAMPLE 2 Substrate treatment, substrate high temperature cleaning, low temperature buffer layer formation, and undoped GaN film formation were performed in the same manner as described in Example 1. Then set the temperature to 1
The temperature was lowered to 000 ° C., and a thin film was formed on the undoped GaN film by adding the film forming condition of Comparative Example 1 to the condition that TMI as an In source gas was caused to flow by 10% with respect to the Ga source gas 1.
After the film formation, the same method as in Comparative Example 1 was used. After cooling, MO
When the substrate with the film was taken out from the CVD device and hole measurement was performed, it showed high resistance. The substrate with the film taken out from the MOCVD apparatus was annealed at 750 ° C. for 30 minutes in a nitrogen gas atmosphere, and hole measurement was performed to show a p-type.

[0024]

COMPARATIVE EXAMPLE 3 Substrate treatment, substrate high temperature cleaning, low temperature buffer layer formation, undoped GaN film, and first gallium indium nitride film formation were carried out in the same manner as described in Example 1. After that, the main carrier gas was switched from hydrogen gas to nitrogen gas and flowed at 8 liters / minute,
TMG while flowing ammonia at 3.5 l / min
Carrier gas at a flow rate of 10 cc / min, TMI as an In source gas at 10% relative to the Ga source gas 1, and Cp ₂ Mg as an Mg source gas at 0.15 relative to the Ga source gas 1, The second gallium indium nitride film was formed by holding at 1000 ° C. for 10 minutes. After that, TMG, TM
I, Cp ₂ Mg was stopped, the main carrier gas was nitrogen gas at 8 liters / minute, and ammonia was made to flow at 3.5 liters / minute, while cooling to 850 ° C. at a cooling rate of about 10 ° C./minute.
At 50 ° C. or lower, the temperature was naturally cooled to room temperature while flowing only nitrogen gas. After cooling, the substrate with the film was taken out from the MOCVD apparatus, and hole measurement was performed, which showed high resistance. After the second film was removed by the RIE method, hole measurement was performed, and it was a semi-insulating material having high resistance and a resistivity of 10 ⁵ Ω · cm or more. The substrate with the film taken out from the MOCVD apparatus was annealed in a nitrogen gas atmosphere at 750 ° C. for 30 minutes, and hole measurement was performed to show p-type.
Furthermore, after the second film was removed by the RIE method, hole measurement was performed, and it was found to be p-type.

[0025]

COMPARATIVE EXAMPLE 4 Substrate treatment, substrate high temperature cleaning, low temperature buffer layer formation, and undoped GaN film formation were carried out in the same manner as described in Example 1. Then set the temperature to 1
The temperature was lowered to 000 ° C., and hydrogen gas was 8 liters / minute, ammonia was 3.5 liters / minute, and carrier gas for TMG was 40 c as main carrier gas on the undoped GaN film.
While flowing at c / min, TMI as an In source gas is 10% with respect to the Ga source gas 1 and Cp ₂ Mg as an Mg source gas is 0.2% with respect to the Ga source gas 1 and 10%.
Then, the first gallium indium nitride film was formed.
After that, TMG, TMIn, and Cp ₂ Mg were stopped, the main carrier gas was switched from hydrogen gas to nitrogen gas, and flowed at 8 liters / minute, while flowing ammonia at 3.5 liters / minute, the cooling rate was about 10 ° C./minute. To 900 ° C. 9
A carrier gas for TMG was flown again at 00 ° C. at 10 cc / min, TMI as an In source gas was 10% with respect to the Ga source gas 1, and Cp ₂ Mg as an Mg source gas was 0.08 with respect to the Ga source gas 1. %, And the mixture was held for 10 minutes to form a second gallium indium nitride film. After forming the film, it was naturally cooled while flowing only nitrogen gas. After cooling, take out the substrate with the film from the MOCVD device,
The Hall measurement showed high resistance. After the second film was removed by the RIE method, hole measurement was performed, and it was a semi-insulating material having high resistance and a resistivity of 10 ⁵ Ω · cm or more. MO
The substrate with the film taken out from the CVD apparatus was annealed in a nitrogen gas atmosphere at 750 ° C. for 30 minutes, and hole measurement was performed to show p-type.
After removing the film, the hole measurement showed a p-type.

According to the growth method of the present invention, it is possible to form a low-resistance p-type aluminum gallium indium nitride having a high hole concentration with an as-grown without the need for an annealing treatment after film formation, and to improve the manufacturing efficiency. An excellent method can be obtained.

Claims (2)

[Claims] 1. A method for producing a gallium nitride-based compound semiconductor using an organometallic vapor phase epitaxy method, which comprises using an organometallic raw material containing each metal of indium, aluminum and gallium, and mainly using hydrogen. In the atmosphere as an ingredient,
After growing the first aluminum gallium indium nitride compound semiconductor layer doped with p-type impurities in the temperature range of 950 ° C. to 1100 ° C., nitrogen is the main component on the aluminum gallium indium indium compound semiconductor layer. In the atmosphere, a high-resistance second aluminum gallium indium nitride compound semiconductor layer doped with p-type impurities is grown in a temperature range of 950 ° C. to 750 ° C., and then naturally cooled to room temperature. Method of manufacturing gallium compound semiconductor. 2. The first aluminum gallium indium nitride compound semiconductor has a resistivity of 10 Ω · cm or less, and the second aluminum gallium indium nitride compound semiconductor has a resistivity of 10 ⁶ Ω · cm or more. The method for producing a gallium nitride-based compound semiconductor according to claim 1, wherein the method is a compound semiconductor having resistance.