JP3239622B2 - Method of forming semiconductor thin film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a blue or shorter wavelength semiconductor laser device which can be used as a light source for an information processing device such as a green / blue light emitting diode or an optical disk. It relates to a method for forming a thin film.

[0002]

2. Description of the Related Art In 1988, 670 nm band AlGaIn
Since the P-based red semiconductor laser was commercialized, short-wavelength semiconductor lasers have been actively developed as light sources for information processing devices such as laser printers and optical disks. Initially, the center of development was 670-690 nm, but with the demand for improved bar code reader visibility and higher density optical discs, the wavelength range has shifted to the 630 nm band, which is the same level as He-Ne gas lasers. I am doing it. Further, in the future, with the increase in storage capacity, there is a long-awaited realization of a semiconductor laser ranging from blue and green having a shorter wavelength than red to an ultraviolet region.
With the possibility of controlling the p-type conductivity, research on group 2-6 semiconductor lasers has been rapidly progressing. on the other hand,
Gallium nitride (GaN) is a direct transition type compound semiconductor having a wide energy gap of about 3.4 eV and is a promising material as a light emitting element in a blue to ultraviolet region.
Development of a semiconductor laser has not progressed much because N bulk substrate crystals cannot be easily produced and there is no other good substrate crystal.

As a method for producing a GaN thin film, α-Al
_A method of vapor phase growth on a ₂ O ₃ (sapphire) substrate by MOVPE (metal organic chemical vapor deposition) is generally used. This is to decompose and react trimethylgallium and ammonia on a substrate heated to about 1050 ° C., for example, a sapphire surface to grow a GaN thin film. Recently, it has been demonstrated that a (0001) C plane of sapphire can be used to form a relatively high-quality GaN thin film via a GaN or AlN non-single-crystal layer. However, since there is a very large lattice mismatch of 13.8% and a large difference in thermal expansion coefficient between the sapphire C-plane and GaN, the relaxation of the lattice mismatch through the non-single-crystal layer is efficient. still 10 ⁸ cm ^-2 or more misfit dislocations but occur could not exist a high-quality thin film formative.

[0004] The problems in crystal growth of AlGaInN quaternary mixed crystal thin films containing Al and In are that, besides the fact that there is no good substrate crystal lattice-matching as described above, ammonia The decomposition efficiency of InN is low, and the decomposition temperature of InN is lower than those of AlN and GaN.

Since the decomposition of ammonia requires a high temperature,
As described above, it was necessary to set the substrate temperature to 900 to 1100 ° C. For this reason, many nitrogen vacancies are generated in the film,
The grown GaN layer becomes a thin film exhibiting n-type conductivity as it is, and has a drawback that it is difficult to obtain a high-resistance GaN thin film. Therefore, the supply ratio of group 3 and group 5,
The so-called 3/5 ratio had to be increased from 1000 to 5000 by one to two orders of magnitude compared to other material systems. It is desirable to grow at a temperature as low as possible, but since ammonia has a very high decomposition temperature, an extremely large amount of ammonia is required even when growing at a low temperature, which is beyond the range that can be supplied practically.

In the case where AlGaInN is grown at about 1000 ° C. using ammonia, In is easily desorbed from the substrate surface because ammonia has a low decomposition efficiency.
Since the amount of In incorporated by the decomposition of InN is remarkably small, control of the composition is difficult, and the morphology of the surface is deteriorated, so that it is difficult to obtain a high-quality AlGaInN thin film.

[0007]

According to the above prior art, the crystal growth of the nitride film could not be performed at a relatively low temperature because ammonia was used as a nitrogen source for the crystal growth. Therefore, large thermal convection occurs on the substrate during MOVPE growth, making it difficult to supply a uniform raw material onto the substrate and controlling the conduction type by impurity doping, ie, growing a p-type conduction nitride film. Was. The present invention enables crystal growth with excellent controllability at a low temperature to obtain a high-quality AlGaInN thin film having few nitrogen vacancies, and easily converts the n-type or p-type conductivity by impurity doping. AlGaInN with controllable conduction type
It is an object to provide a method for forming a thin film. Especially In
It is a main object of the present invention to provide a method for forming an AlGaInN thin film containing.

Further, according to the prior art, the lattice constant of the nitride film and that of the sapphire substrate are poorly matched, and the difference in thermal expansion coefficient is large. It was difficult to grow a nitride film having good flatness.

According to the present invention, a thin film can be formed at a lower temperature than before,
An object of the present invention is to provide a method for forming an AlGaInN thin film having few dislocations and good flatness.

Furthermore, according to the prior art, sapphire was used as a substrate, but processing was difficult and device fabrication was not easy. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming an AlGaInN thin film that is uniform and has good flatness on a substrate that is inexpensive and easy to process.

[0011]

According to a first aspect of the present invention, there is provided a method for forming a semiconductor thin film, comprising supplying a raw material containing a group 3 constituent element and a raw material containing nitrogen onto a heated substrate surface. To form an AlGaInN thin film through a buffer layer,
A method of forming an N layer and forming an AlGaInN layer on the GaN layer at a substrate temperature set within a range of 300 to 900 ° C., wherein the AlGaInN layer is formed by mixing a hydrazine-based material with ammonia. Or a mixed raw material of an alkylamine-based substance and ammonia as a nitrogen raw material
The AlGaInN layer is made of a raw material containing a group 3 constituent element.
Supply is performed intermittently to form the InN layer and the AlGaN layer.
It is formed by repeatedly supplying raw materials .

According to a second aspect of the present invention, there is provided a method of forming a semiconductor thin film .
A raw material containing a Group 3 constituent element and a raw material containing nitrogen are supplied onto the heated substrate surface, and Al _x1 Ga _y1 is supplied through a buffer layer.
An In _z1 N layer / Al _x2 Ga _y2 In _z2 N layer / Al _x3 Ga _y3 In
_z3 N layer _{(Eg 2 <Eg 1, Eg} 3: Eg is the band gap) in a method of forming a multilayer AlGaInN thin film made to form a GaN layer at 9 00 ° C. above the substrate temperature, on the GaN layer 300 Al _x1 Ga lattice-matched to the GaN layer at a substrate temperature set within a range of ９００900 ° C.
Al _x2 Ga _y2 lattice-mismatched with _y1 In _z1 N layer by 2% or less
Al _{x3 Gay 3} lattice-matched to the In _z2 N layer and the GaN layer
A method for forming a an In _z3 N layer, said AlGaIn
The formation of the N multilayer film is based on the formation of a hydrazine-based material and ammonia.
A mixed raw material or a mixed raw material of an alkylamine-based substance and ammonia is used as a nitrogen raw material.

According to a third aspect of the present invention, there is provided a method of forming a semiconductor thin film.
A method for forming a GaN layer through a buffer layer by supplying a raw material containing a Group 3 constituent element and a raw material containing nitrogen on a heated substrate surface, and forming an AlGaInN thin film on the GaN layer. A on the middle or on the GaN layer
Place the strained superlattice structure consisting of lGaInN layer, the A
1GaInN layer intermittently supplies raw materials containing group 3 elements
Of the raw materials constituting the InN layer and the AlGaN layer
It is characterized by being formed by repeated supply .

According to a fourth aspect of the present invention, there is provided a method of forming a semiconductor thin film.
A raw material containing a group 3 constituent element on the heated substrate surface;
Supplying a nitrogen-containing raw material and supplying AlGaIn through a buffer layer
In a method of forming an N thin film, the atmosphere of a carbon-containing material is
Heating the substrate in air to form carbonized
Layer and then a mixture of hydrazine-based material and ammonia
Or mixture of alkylamine-based substance and ammonia
Nitriding formed on the surface of the carbonized layer in an atmosphere containing raw materials
It is characterized in that the layer is at least a buffer layer .

[0015]

[0016]

[0017]

[0018]

[0019]

One of the problems in crystal growth of an AlGaInN thin film is that the growth temperature of InN is lower than that of AlN and GaN.
Is lower than them. That is, when the AlGaInN thin film is grown at the growth temperature of the AlGaN thin film using ammonia, ammonia is low in the decomposition efficiency, so that In is easily desorbed from the substrate surface. Since the amount of In taken in by the decomposition of InN is extremely small, it is difficult to control the composition and the morphology of the surface is deteriorated.

According to the method for forming a semiconductor thin film according to the first or second aspect, since a nitrogen source containing at least an alkylamine-based or hydrazine-based material having a low decomposition temperature is used, it can be grown at a relatively low temperature and has a high growth temperature. As a result, gas convection can be suppressed, and dissociation of In can be suppressed. Therefore, a higher quality AlGaInN thin film or Al
A GaInN multilayer film can be formed. With it,
Hydrazine or alkylamine and ammonia
At low temperature using a nitrogen source containing a mixed source of, for example, In,
Alternate source gases such as N / N / Ga, Al, N / N
By supplying on the substrate, nitrogen vacancies are reduced and In
Higher quality at lower temperatures than before, due to stable incorporation
AlGaInN thin film or AlGaInN multilayer film
Formation is possible.

According to the method of forming a semiconductor thin film according to the third aspect, before forming an AlGaInN thin film, A containing a strain is used.
Since the 1GaInN superlattice is arranged, the dislocation generated from the substrate interface has a large in-plane motion component, so that the propagation to the upper layer can be suppressed efficiently and high quality AlGaIn
An N thin film can be formed. At the same time, if hydrazine
Or a mixture of alkylamines and ammonia
For example, In, N / N / Ga, A
1, raw material gas is alternately supplied on the substrate like N / N
As a result, there are few nitrogen vacancies and stable incorporation of In
Therefore, AlGaInN, which is higher in quality at a lower temperature than in the past,
A thin film can be formed.

One of the problems in crystal growth of the AlGaInN thin film is that there is no lattice matching substrate. Conventionally, a nitride thin film has been formed on a sapphire substrate via a non-single-crystal layer of AlN or GaN. However, the sapphire substrate is difficult to process and is not suitable as a substrate for a semiconductor device. Moreover, since large lattice mismatch and thermal strain still exist between the AlN and GaN non-single-crystal layers, the propagation of dislocations generated at the interface with the substrate cannot be sufficiently suppressed.

[0023]

According to the method of forming a semiconductor thin film according to claim 4, for example, carbon is diffused into the substrate during the heat treatment performed before forming the AlGaInN thin on a silicon substrate, by silicon from the substrate to dissociate, Silicon to Si
A carbonized layer having a continuous composition change to C can be formed. S
Since the lattice constant of iC is close to the lattice constant of nitride, the generation of dislocations is suppressed and the effect of reducing thermal strain is also effective, so that the propagation of dislocations to the AlGaInN thin film can be greatly reduced.

[0025]

As described above, it is possible to form a high-quality AlGaInN thin film on a sapphire or other substrate which can be easily processed, for example, a silicon substrate or a GaP substrate.

Therefore, the present invention is extremely useful for manufacturing a blue semiconductor laser device which can be used for a blue light emitting diode having a high luminous efficiency, a light source for an information processing device, and the like.

[0028]

The present invention will be described below with reference to examples. Hereinafter, the same reference numerals are used for the same parts.

For manufacturing the AlGaInN thin film, a MOVPE apparatus schematically shown in FIG. 1 was used. Here, a quartz gas introduction tube 2 is attached inside the quartz reaction tube 1. A raw material containing a Group 3 constituent element and a raw material containing nitrogen can be simultaneously supplied from a quartz gas introduction tube. A high frequency heating coil 3 is provided on the outer periphery of the quartz reaction tube 1.
A susceptor 4 made of graphite coated with SiC is provided inside. The graphite susceptor 4 is supported by a susceptor support rod 5 that can rotate at about 1000 revolutions / minute by a motor. On the upper surface of the graphite susceptor 4, a substrate 7 mounted on a quartz tray 6 can be installed. An exhaust port 8 connected to a vacuum pump is provided at the bottom of the quartz reaction tube 1 so that the pressure in the quartz reaction tube 1 can be adjusted and gas can be exhausted.

(Embodiment 1) FIG. 2 shows an AlG film formed by the method of forming an AlGaInN thin film according to the first embodiment of the present invention.
1 shows a cross-sectional structure diagram of an aInN thin film. A method of forming an AlGaInN thin film using the MOVPE apparatus of FIG. 1 will be described step by step.

After the (111) plane silicon substrate 11 was organically washed, it was placed as a crystal growth substrate on a quartz tray 6 and introduced into the quartz reaction tube 1. After hydrogen gas was introduced into the quartz reaction tube 1, the pressure inside the quartz reaction tube 1 was reduced to 1/1.
The pressure was set to 0 atm and the graphite susceptor 4
Rotated at rev / min. The susceptor 4 made of graphite was heated to 1200 ° C. in hydrogen gas, and the silicon substrate 11 was heated.
The surface was cleaned. After the temperature of the substrate was lowered to 600 ° C., hydrazine was introduced as a group V material from the quartz gas introduction tube 2 onto the surface of the silicon substrate 11, and one minute later, trimethylgallium was introduced as a group 3 material. After depositing the non-single-crystal GaN layer 12 having a thickness of 20 nm, the introduction of trimethylgallium was stopped. This was used as a buffer layer. Next, the substrate temperature was raised to 1000 ° C., ammonia was added to hydrazine as a Group V raw material, and trimethylgallium was introduced as a Group 3 raw material one minute later. After growing the GaN layer 13 having a thickness of 3 μm, the introduction of trimethylgallium was stopped. After the growth of 3 μm, the surface of the GaN layer 13 became flat, and propagation of defects generated from the substrate interface was significantly reduced. Then, the substrate temperature is decreased to 800 ° C., it was introduced trimethyl gallium, trimethyl aluminum and trimethyl indium simultaneously, the thickness of 0.5 [mu] m Al _0.45
A Ga _0.5 In _0.05 N layer 14 was grown. After stopping the introduction of trimethylgallium, trimethylaluminum and trimethylindium, the temperature of the substrate was lowered to a temperature of 300 ° C. or less, and the introduction of hydrazine and ammonia was stopped. After the temperature of the substrate was lowered to room temperature, the substrate was taken out of the quartz reaction tube 1.

The graphite susceptor 4 is rotated 10 times /
When rotated in minutes, a large amount of
Reaction products adhere, and the resulting crystal surface is uneven and quaternary mixed crystal
While the In composition of the layer was 0.02,
In this case, adhesion of the reaction product to the quartz gas introduction pipe 2 is small.
And the carrier concentration is 10 according to the Hall effect on the mirror surface. ^Fifteen
cm^-3And a quaternary mixed crystal having extremely few defects was obtained. Ma
In addition, the In composition becomes 0.05, and the rotation speed is 800 rpm.
Confirm that the incorporation rate of In increases due to rotation.
Was. It grows at 1000 ° C while it is as low as 800 ° C
A quaternary mixed crystal of higher quality than the GaN layer obtained was obtained. these
The result is that hydrazine and ammonia were introduced at the same time.
Is effective in reducing nitrogen vacancies and suppressing the dissociation of In.
Control of gas flow by high-speed rotation and efficient raw material
It is thought that it is due to the incorporation.

(Embodiment 2) FIG. 3 shows an Al film formed by the method for forming an AlGaInN multilayer film according to a second embodiment of the present invention.
FIG. 3 is a sectional structural view of a GaInN multilayer film. MOVP of FIG.
A method for forming an AlGaInN multilayer film using the E apparatus will be described step by step.

After the (111) plane silicon substrate 11 was organically washed, it was arranged as a crystal growth substrate on a quartz tray 6 and introduced into the quartz reaction tube 1. After hydrogen gas was introduced into the quartz reaction tube 1, the pressure inside the quartz reaction tube 1 was reduced to 1/1.
The pressure was set to 0 atm and the graphite susceptor 4
Rotated at rev / min. The susceptor 4 made of graphite was heated to 1200 ° C. in hydrogen gas, and the silicon substrate 11 was heated.
The surface was cleaned. After the temperature of the substrate was lowered to 600 ° C., hydrazine was introduced as a group V material from the quartz gas introduction tube 2 onto the surface of the silicon substrate 11, and one minute later, trimethylgallium was introduced as a group 3 material.

After depositing the non-single-crystal GaN layer 12 having a thickness of 20 nm, the introduction of trimethylgallium was stopped. This was used as a buffer layer. Next, the substrate temperature is set to 1000 ° C.
Then, ammonia was introduced in addition to hydrazine as a Group V raw material, and one minute later, trimethylgallium was introduced as a Group 3 raw material. After growing the GaN layer 13 having a thickness of 3 μm, the introduction of trimethylgallium was stopped.

After the growth of 3 μm, the surface of the GaN layer 13 became flat, and the propagation of defects generated from the substrate interface was significantly reduced. Next, the substrate temperature was lowered to 800 ° C., trimethylgallium, trimethylaluminum and trimethylindium were simultaneously introduced, and a 1.0 μm-thick Al _0.45 Ga _0.5 In _0.05 N layer 15 lattice-matched to the GaN layer 13.
Grew. After stopping the introduction of trimethylgallium, trimethylaluminum and trimethylindium, the substrate temperature is lowered to 700 ° C., trimethylgallium and trimethylindium are simultaneously introduced, and a Ga _0.8 In _0.2 N layer having a lattice irregularity having a thickness of 0.01 μm is formed. 16 grew. Next, after stopping the introduction of trimethylgallium and trimethylindium, the substrate temperature was raised to 800 ° C., trimethylgallium, trimethylaluminum and trimethylindium were simultaneously introduced, and a 1.0 μm thick film lattice-matched to the GaN layer 13 was formed. Al _0.45 Ga _0.5 In _0.05 N layer 17
Grew again. After stopping the introduction of trimethylgallium, trimethylaluminum and trimethylindium,
When the substrate temperature was lowered to 300 ° C. or less, the introduction of hydrazine and ammonia was stopped. After the temperature of the substrate was lowered to room temperature, the substrate was taken out of the quartz reaction tube 1.

The surface of the obtained AlGaInN multilayer film is a mirror surface, and as a result of photoluminescence measurement, Ga _0.8
Strong light emission from the In _0.2 N layer 16 was confirmed.

The graphite susceptor 4 was rotated 10 times /
When rotated in minutes, a large amount of reaction products adhere to the quartz gas introduction tube 2, and the resulting crystal surface is uneven and GaIn
While the In composition of the N layer was 0.12, in the case of the present embodiment, adhesion of the reaction product to the quartz gas introduction tube 2 was small, and the In composition was 0.2, which was 800 rpm. It was confirmed that the rate of In was increased by the rotation of. 800 ° C
Thus, a multilayer film containing In of higher quality than GaN grown at 1000 ° C. at a low temperature was obtained. These results are the effects of reducing nitrogen vacancies and suppressing the dissociation of In due to simultaneous introduction of hydrazine and ammonia, and are considered to be due to suppression of convection of the gas flow by high-speed rotation and efficient incorporation of raw materials.

Further, even when GaInN having a lattice irregularity is introduced, a multilayer film can be formed while maintaining the same crystallinity as that of a lattice-matched mixed crystal.

(Embodiment 3) FIG. 4 shows an AlG film formed by a method of forming an AlGaInN thin film according to a third embodiment of the present invention.
1 shows a cross-sectional structure diagram of an aInN thin film. A method for manufacturing an AlGaInN thin film using the MOVPE apparatus of FIG. 1 will be described step by step.

After the (111) plane silicon substrate 11 was organically washed, it was placed as a crystal growth substrate on a quartz tray 6 and introduced into the quartz reaction tube 1. After hydrogen gas was introduced into the quartz reaction tube 1, the pressure inside the quartz reaction tube 1 was reduced to 1/1.
The pressure was set to 0 atm and the graphite susceptor 4
Rotated at rev / min. The susceptor 4 made of graphite was heated to 1200 ° C. in hydrogen gas, and the silicon substrate 11 was heated.
The surface was cleaned. After the temperature of the substrate was lowered to 600 ° C., hydrazine was introduced as a group V material from the quartz gas introduction tube 2 onto the surface of the silicon substrate 11, and one minute later, trimethylgallium was introduced as a group 3 material. After depositing the non-single-crystal GaN layer 12 having a thickness of 20 nm, the introduction of trimethylgallium was stopped. This was used as a buffer layer.

Next, the substrate temperature was raised to 1000 ° C.
Ammonia was introduced in addition to hydrazine as a Group V raw material, and one minute later, trimethylgallium was introduced as a Group 3 raw material. After growing the GaN layer 13 having a thickness of 3 μm, the introduction of trimethylgallium was stopped. When growing 3 μm, G
The surface of the aN layer 13 became flat, and the propagation of defects generated from the substrate interface was significantly reduced. Next, the substrate temperature is set to 80
The temperature was lowered to 0 ° C., and trimethylgallium and trimethylaluminum were simultaneously introduced to form a 2 nm-thick Al _0.3 Ga _0.7 N
Layer 18 was grown. After stopping the introduction of trimethylgallium and trimethylaluminum, trimethylgallium and trimethylindium were simultaneously introduced, and a G film having a thickness of 2 nm was formed.
An a _0.8 In _0.2 N layer 19 was grown. After growing the continuously 40 cycles of _{Al 0.3 Ga 0.7 N / Ga 0.8} In 0.2 N strained superlattice 20, thickness 2μm introducing trimethylgallium again
And the introduction of trimethylgallium was stopped. Next, trimethylgallium, trimethylaluminum and trimethylindium were simultaneously introduced to grow an Al _0.45 Ga _0.5 In _0.05 N layer 14 having a thickness of 0.5 μm. After stopping the introduction of trimethylgallium, trimethylaluminum and trimethylindium, the temperature of the substrate was lowered to a temperature of 300 ° C. or less, and the introduction of hydrazine and ammonia was stopped. After the temperature of the substrate was lowered to room temperature, the substrate was taken out of the quartz reaction tube 1.

By introducing the Al _0.3 Ga _0.7 N / Ga _0.8 In _0.2 N strained superlattice 20, the propagation of the defect generated from the substrate interface is remarkably suppressed. Was reduced. According to the Hall effect, the carrier concentration is 10 ¹⁵ cm.
^-3 or less, a GaN layer grown at 1000 ° C. while the growth temperature was as low as 800 ° C., and a quaternary mixed crystal of higher quality than in Example 1 were obtained.

(Embodiment 4) FIG. 5 shows an Al fabricated by a method of forming an AlGaInN multilayer film according to a fourth embodiment of the present invention.
FIG. 3 is a sectional structural view of a GaInN multilayer film. MOVP of FIG.
A method for forming an AlGaInN multilayer film using the E apparatus will be described step by step.

After the (111) plane silicon substrate 11 was organically washed, it was placed on a quartz tray 6 as a crystal growth substrate and introduced into the quartz reaction tube 1. After hydrogen gas was introduced into the quartz reaction tube 1, the pressure inside the quartz reaction tube 1 was reduced to 1/1.
The pressure was set to 0 atm and the graphite susceptor 4
Rotated at rev / min. The susceptor 4 made of graphite was heated to 1200 ° C. in hydrogen gas, and the silicon substrate 11 was heated.
The surface was cleaned. After the temperature of the substrate was lowered to 600 ° C., hydrazine was introduced as a group V material from the quartz gas introduction tube 2 onto the surface of the silicon substrate 11, and one minute later, trimethylgallium was introduced as a group 3 material. After depositing the non-single-crystal GaN layer 12 having a thickness of 20 nm, the introduction of trimethylgallium was stopped. This was used as a buffer layer.

Next, the substrate temperature is raised to 1000 ° C.
Ammonia was introduced in addition to hydrazine as a Group V raw material, and one minute later, trimethylgallium was introduced as a Group 3 raw material. After growing the GaN layer 13 having a thickness of 3 μm, the introduction of trimethylgallium was stopped. When growing 3 μm, G
The surface of the aN layer 13 became flat, and the propagation of defects generated from the substrate interface was significantly reduced. Next, the substrate temperature is set to 80
The temperature was lowered to 0 ° C., and trimethylgallium, trimethylaluminum and trimethylindium were introduced simultaneously,
1.0 μm-thick Al _0.45 Ga lattice-matched to layer 13
_{A 0.5} In _0.05 N layer 15 was grown. After stopping the introduction of trimethylgallium, trimethylaluminum and trimethylindium, the substrate temperature was lowered to 600 ° C.
Next, as shown in the source gas supply procedure of FIG. 6A, trimethylindium was introduced and InN22 was changed to 1 nm.
After the growth, trimethylindium was stopped, trimethylgallium and trimethylaluminum were introduced, and 1 nm
Of AlGaN 23 was grown. In this way, the mixture was alternately supplied 30 times.

Thus, the pseudo AlGaInN layer 24
Was formed. After stopping the introduction of trimethylgallium and trimethylaluminum, the substrate temperature was raised to 800 ° C., trimethylgallium, trimethylaluminum and trimethylindium were simultaneously introduced, and a 0.4 μm thick Al _0.45 lattice-matched to the GaN layer 13 was formed. Ga _0.5 In _{0.0 5}
The N layer 17 was grown again. After stopping the introduction of trimethylgallium, trimethylaluminum and trimethylindium, the temperature of the substrate was lowered to a temperature of 300 ° C. or less, and the introduction of hydrazine and ammonia was stopped. After the temperature of the substrate was lowered to room temperature, the substrate was taken out of the quartz reaction tube 1.

The surface of the obtained AlGaInN multilayer film is a mirror surface, and as a result of photoluminescence measurement,
A pseudo A consisting of a strained superlattice of two layers and 23 layers of AlGaN
Strong light emission from the lGaInN layer 24 was confirmed. According to the present invention, it was possible to obtain light emission having a long wavelength of 500 nm or more, which could not be achieved until now, as compared with the conventional method and the formation method shown in Example 2.

Similar results were obtained in the forming method shown in the source gas supply procedure of FIG.

(Embodiment 5) FIG. 7 shows an AlG film formed by the method of forming an AlGaInN thin film according to a fifth embodiment of the present invention.
1 shows a cross-sectional structure diagram of an aInN thin film. A method of forming an AlGaInN thin film using the MOVPE apparatus of FIG. 1 will be described step by step.

After the (111) plane silicon substrate 11 was organically washed, it was placed as a crystal growth substrate on a quartz tray 6 and introduced into the quartz reaction tube 1. After hydrogen gas was introduced into the quartz reaction tube 1, the pressure inside the quartz reaction tube 1 was reduced to 1/1.
The pressure was set to 0 atm and the graphite susceptor 4
Rotated at rev / min. The susceptor 4 made of graphite was heated to 1200 ° C. in hydrogen gas, and the silicon substrate 11 was heated.
The surface was cleaned. Methane gas was introduced to form a carbonized layer 25 on the substrate surface. After the temperature of the substrate was lowered to 600 ° C., hydrazine was introduced as a group V material from the quartz gas introduction tube 2 onto the surface of the silicon substrate 11, and one minute later, trimethylgallium was introduced as a group 3 material. After depositing the non-single-crystal GaN layer 12 having a thickness of 20 nm, the introduction of trimethylgallium was stopped. This was used as a buffer layer. Next, the substrate temperature was raised to 1000 ° C., ammonia was added to hydrazine as a Group V raw material, and trimethylgallium was introduced as a Group 3 raw material one minute later.

After growing a GaN layer 13 having a thickness of 3 μm,
The introduction of trimethylgallium was stopped. After the growth of 3 μm, the surface of the GaN layer 13 became flat, and propagation of defects generated from the substrate interface was significantly reduced. Next, the substrate temperature was lowered to 800 ° C., and trimethylgallium, trimethylaluminum and trimethylindium were simultaneously introduced,
An Al _0.45 Ga _0.5 In _0.05 N layer 14 having a thickness of 0.5 μm was grown. After stopping the introduction of trimethylgallium, trimethylaluminum and trimethylindium, the temperature of the substrate was lowered to a temperature of 300 ° C. or less, and the introduction of hydrazine and ammonia was stopped. After the temperature of the substrate was lowered to room temperature, the substrate was taken out of the quartz reaction tube 1.

According to the present invention, the crystal surface obtained is a mirror surface and the carrier concentration is 10 ¹⁵ cm ⁻³ or less according to the Hall effect, and the growth temperature is as low as 800 ° C. and 100 ° C.
A GaN layer grown at 0 ° C. and a quaternary mixed crystal of higher quality than in the case of Example 1 were obtained. In addition, by carbonizing the surface of the silicon substrate 11, the generation of defects from the substrate interface was significantly suppressed, and the number of defects was reduced by about two digits as compared with the case of Example 1.

This method has no effect when a sapphire substrate is used, and is extremely effective when a silicon substrate is used.

(Embodiment 6) FIG. 8 shows an AlGN fabricated by the method of forming an AlGaInN thin film according to a sixth embodiment of the present invention.
1 shows a cross-sectional structure diagram of an aInN thin film. A method of forming an AlGaInN thin film using the MOVPE apparatus of FIG. 1 will be described step by step.

After the (111) plane silicon substrate 11 was organically washed, it was placed as a crystal growth substrate on a quartz tray 6 and introduced into the quartz reaction tube 1. After hydrogen gas was introduced into the quartz reaction tube 1, the pressure inside the quartz reaction tube 1 was reduced to 1/1.
The pressure was set to 0 atm and the graphite susceptor 4
Rotated at rev / min. The susceptor 4 made of graphite was heated to 1200 ° C. in hydrogen gas, and the silicon substrate 11 was heated.
The surface was cleaned. Methane gas was introduced to form a carbonized layer 25 on the substrate surface. Thereafter, the introduction of methane gas was stopped, and hydrazine was introduced to form a nitrided layer 26 on the carbonized layer 25. After the temperature of the substrate was lowered to 600 ° C., hydrazine was introduced as a group V material from the quartz gas introduction tube 2 onto the surface of the silicon substrate 11, and one minute later, trimethylgallium was introduced as a group 3 material. Non-single-crystal Ga with a thickness of 20 nm
After depositing the N layer 12, the introduction of trimethylgallium was stopped. This was used as a buffer layer.

Next, the substrate temperature was raised to 1000 ° C.
Ammonia was introduced in addition to hydrazine as a Group V raw material, and one minute later, trimethylgallium was introduced as a Group 3 raw material. After growing the GaN layer 13 having a thickness of 3 μm, the introduction of trimethylgallium was stopped. When growing 3 μm, G
The surface of the aN layer 13 became flat, and the propagation of defects generated from the substrate interface was significantly reduced. Next, the substrate temperature is set to 80
The temperature was lowered to 0 ° C., and trimethylgallium, trimethylaluminum and trimethylindium were simultaneously introduced to grow an Al _0.45 Ga _0.5 In _0.05 N layer 14 having a thickness of 0.5 μm. After stopping the introduction of trimethylgallium, trimethylaluminum and trimethylindium, the temperature of the substrate was lowered to a temperature of 300 ° C. or less, and the introduction of hydrazine and ammonia was stopped. After the temperature of the substrate was lowered to room temperature, the substrate was taken out of the quartz reaction tube 1.

In the case of this embodiment, the obtained crystal surface is a mirror surface and the carrier concentration is 10 ¹⁵ cm ⁻³ or less according to the Hall effect, and the growth temperature is as low as 800 ° C.
A GaN layer grown at 00 ° C., and a higher quality quaternary mixed crystal than in Example 1 were obtained. Further, by carbonizing the surface of the silicon substrate 11, the generation of defects from the substrate interface was significantly suppressed. In addition, since GaN grows easily and densely by nucleating the surface by nitriding,
Defects were further reduced as compared with the case of.

This method has no effect when a sapphire substrate is used, and is extremely effective when a silicon substrate is used.

(Embodiment 7) FIG. 9 shows an AlGN fabricated by the method of forming an AlGaInN thin film according to a seventh embodiment of the present invention.
1 shows a cross-sectional structure diagram of an aInN thin film. A method of forming an AlGaInN thin film using the MOVPE apparatus of FIG. 1 will be described step by step.

After the (111) -plane GaP substrate 27 is organically washed, it is placed on a quartz tray 6 as a crystal growth substrate.
It was introduced into the reaction tube 1 made of quartz. After introducing hydrogen gas into the quartz reaction tube 1, the pressure in the quartz reaction tube 1 was set to 1/10 atm, and the graphite susceptor 4 was rotated 800 times.
Rotated at / min. The susceptor 4 made of graphite was heated to 800 ° C. in a phosphine atmosphere, and the GaP substrate 27 was heated.
The surface was cleaned. The introduction of phosphine was stopped, hydrazine was introduced, and a nitride layer 28 was formed on the substrate surface. After lowering the substrate temperature to 600 ° C., the quartz gas introduction pipe 2
Introduced trimethylgallium as a Group 3 raw material on the surface of the GaP substrate 27. Non-single-crystal GaN layer 1 having a thickness of 20 nm
After the deposition of 2, the introduction of trimethylgallium was stopped. This was used as a buffer layer. Then, the substrate temperature was set to 1
The temperature was raised to 000 ° C., ammonia was introduced in addition to hydrazine as a Group V raw material, and one minute later, trimethylgallium was introduced as a Group 3 raw material.

After growing a GaN layer 13 having a thickness of 3 μm,
The introduction of trimethylgallium was stopped. After the growth of 3 μm, the surface of the GaN layer 13 became flat, and propagation of defects generated from the substrate interface was significantly reduced. Next, the substrate temperature was lowered to 800 ° C., and trimethylgallium, trimethylaluminum and trimethylindium were simultaneously introduced,
An Al _0.45 Ga _0.5 In _0.05 N layer 14 having a thickness of 0.5 μm was grown. After stopping the introduction of trimethylgallium, trimethylaluminum and trimethylindium, the temperature of the substrate was lowered to a temperature of 300 ° C. or less, and the introduction of hydrazine and ammonia was stopped. After the temperature of the substrate was lowered to room temperature, the substrate was taken out of the quartz reaction tube 1.

According to the present invention, the obtained crystal surface is a mirror surface and the carrier concentration is 10 ¹⁵ cm ⁻³ or less according to the Hall effect, and GaP is used for the substrate, but the same as AlGaInN formed on sapphire. Of quaternary mixed crystal of high quality was obtained. Further, by nitriding the surface of the GaP substrate 27, the generation of defects from the substrate interface was significantly suppressed, and the defects were reduced to the same extent as the sapphire substrate.

This forming method was extremely effective for a GaP substrate. The present invention is not limited to the embodiments described above. For example, the substrate used is not limited to the above-described substrate. The raw materials used for crystal growth are not limited to those described above. The configuration of the AlGaInN multilayer film is not limited.

[0065]

As described above, according to the present invention, an alkylamine-based material, a hydrazine-based or alkylamine-based material, or a mixed material of hydrazine-based and ammonia is used as a nitrogen material, and the substrate is rotated at a high speed. The AlGaInN thin film containing In with few point defects can be easily formed at a low temperature.

Further, since the AlGaInN thin film is constituted by an ultra-thin multilayer film in which InN and AlGaN are alternately formed, a higher quality AlGaInN thin film can be formed.

Prior to the formation of the AlGaInN thin film, A
Since the 1GaInN strained superlattice structure is formed, propagation of dislocations is significantly reduced, and a high-quality AlGaInN thin film can be formed.

Further, since a carbonized layer or a nitrided layer whose composition continuously changes is formed prior to a non-single-crystal layer such as GaN, propagation of dislocations is remarkably reduced, and high-quality AlGaInN is formed on a substrate other than sapphire. Can be formed.

Therefore, the present invention is extremely useful for manufacturing a blue semiconductor laser device which can be used for a blue light emitting diode having a high luminous efficiency, a light source for an information processing device, and the like.

[Brief description of the drawings]

FIG. 1 is an MOV illustrating a forming method according to an embodiment of the present invention.
Schematic diagram of PE device

FIG. 2 is a sectional structural view of an AlGaInN thin film formed by the method for forming an AlGaInN thin film according to the first embodiment of the present invention;

FIG. 3 is a sectional structural view of an AlGaInN multilayer film according to a method of forming an AlGaInN multilayer film according to a second embodiment of the present invention;

FIG. 4 is a sectional structural view of an AlGaInN thin film formed by a method for forming an AlGaInN thin film according to a third embodiment of the present invention;

FIG. 5 is a sectional structural view of an AlGaInN thin film by a method of forming an AlGaInN multilayer film according to a fourth embodiment of the present invention.

FIG. 6 is a supply procedure diagram of a source gas according to a fourth embodiment of the present invention.

FIG. 7 is a sectional structural view of an AlGaInN thin film according to a fifth embodiment of the present invention;

FIG. 8 is a sectional structural view of an AlGaInN thin film according to a sixth embodiment of the present invention;

FIG. 9 is a sectional structural view of an AlGaInN thin film formed by a method of forming an AlGaInN thin film according to a seventh embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Quartz reaction tube 2 Quartz gas introduction tube 3 High frequency heating coil 4 Graphite susceptor 5 Susceptor support rod 6 Quartz tray 7 Substrate 8 Exhaust port 11 Silicon substrate 12 Non-single-crystal GaN layer 13, 21 GaN layer 14, 15 , 17 Al _0.45 Ga _0.5 In _0.05 N layer 16, 19 Ga _0.8 In _0.2 N layer 18 Al _0.3 Ga _0.7 N layer 20 Al _0.3 Ga _0.7 N / Ga _0.8 In _0.2 N strained superlattice 22 InN layer 23 AlGaN layer 24 pseudo AlGaInN layer 25 Carbide layer 26, 28 Nitride layer 27 GaP substrate

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-109621 (JP, A) JP-A-6-1965757 (JP, A) JP-A-6-216409 (JP, A) JP-A-4- 372120 (JP, A) JP-A-4-223330 (JP, A) JP-A-5-41541 (JP, A) JP-A-5-190903 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) H01L 33/00 H01L 21/205 H01S 5/00-5/50

Claims (4)

(57) [Claims] 1. A method for forming a thin film of AlGaInN via a buffer layer by supplying a raw material containing a Group 3 constituent element and a raw material containing nitrogen on a heated substrate surface,
A GaN layer is formed at a substrate temperature of at least 300 ° C., and Al is formed on the GaN layer at a substrate temperature set within a range of 300 to 900 ° C.
A method for forming a GaInN layer, comprising:
formation of nN layer material mixture with a hydrazine-based material and ammonia, or a mixed raw material of alkyl amine-based material and ammonia as a nitrogen source, the AlGaInN layer 3 group
Supply of the raw material containing the constituent elements is performed intermittently,
Formed by repeated supply of the raw material that constitutes the AlGaN layer
A method of forming a semiconductor thin film. 2. An Al _x1 Ga _y1 In _z1 N layer / Al _x2 Gay _y2 In _z2 N layer via a buffer layer by supplying a raw material containing a group III constituent element and a raw material containing nitrogen onto a heated substrate surface. /
Al _x3 Ga _y3 In _z3 N layer (Eg2 <Eg1, Eg3: E
g is a band gap) in the method of forming an AlGaInN multilayer film.
An N layer is formed, and on the GaN layer, an Al _x1 Ga _y1 In _z1 N layer lattice-matched to the GaN layer at a substrate temperature set within a range of 300 to 900 ° C. and a lattice mismatch A of 2% or less.
l _x2 Ga _y2 In _z2 N layer A lattice-matched to the GaN layer
A method of forming a l _x3 Ga _y3 In _z3 N layer, the A
The formation of the lGaInN multilayer film is characterized in that a mixed material of a hydrazine-based material and ammonia or a mixed material of an alkylamine-based material and ammonia is used as a nitrogen material .
Method of forming a semiconductor thin film . 3. A GaN layer is formed via a buffer layer by supplying a raw material containing a Group 3 constituent element and a raw material containing nitrogen onto a heated substrate surface, and forming an AlGaInN layer on the GaN layer.
In the method of forming a thin film, a strained superlattice structure composed of an AlGaInN layer is arranged in or on the GaN layer, and the AlGaInN layer is an original containing a group 3 element.
The supply of material is performed intermittently, and the InN layer and the AlGaN layer are composed.
A method for forming a semiconductor thin film, wherein the semiconductor thin film is formed by repeatedly supplying a raw material to be formed. 4. A group III constituent element on a heated substrate surface.
And a nitrogen-containing material are supplied through the buffer layer.
A method of forming a AlGaInN thin Te, carbon
Heating the substrate in the atmosphere of the raw material containing
The hydrazine-based material and the
Raw material mixed with near
On the surface of the carbonized layer in an atmosphere containing a raw material mixed with monia
Characterized in that the nitride layer formed on the substrate is at least a buffer layer.
Forming a semiconductor thin film.