JP2001148543A - Method of manufacturing iii nitride semiconductor, and method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the performance of a light-emitting element and make its service life long by forming a III nitride semiconductor layer, having no dislocation on a substrate. SOLUTION: This manufacturing method comprises steps of epitaxially growing a first III nitride semiconductor layer 12 on a substrate 11, removing first portions of the first III nitride semiconductor layer 12, while leaving prescribed portions, epitaxially growing a crystal to regions formed by the removal from the first portions of the first III nitride semiconductor layer 12 left to form a second III nitride semiconductor layer 14, removing at least the left first III nitride semiconductor layer 12, while leaving prescribed portions of the second III nitride semiconductor layer 14, and epitaxially growing a crystal from the left second III nitride semiconductor layer 14 to regions formed by the removal, to form a third III nitride semiconductor layer 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a group III nitride semiconductor and a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a group III nitride semiconductor in which etching and epitaxial growth are repeated after epitaxial growth, and the above manufacturing method. The present invention relates to a method for manufacturing a semiconductor device in which a semiconductor element is formed using a group III nitride semiconductor layer formed by the method described above.

[0002]

2. Description of the Related Art Gallium nitride (GaN), a kind of group III nitride semiconductor, has a bandgap of 3.4 e in GaN.
V and a direct transition type have attracted attention as a blue light emitting element material. However, it is difficult to obtain a lattice-matched substrate with a thermal expansion coefficient close to that of a group III nitride semiconductor. Generally, gallium nitride is grown on a sapphire substrate via a buffer layer obtained by growing gallium nitride or aluminum nitride at low temperature. I was

[0003]

However, due to differences in lattice constant and thermal expansion coefficient between gallium nitride and a sapphire substrate, cracks and dislocation densities of 1 × 10 ⁹
/ Cm ² to 1 × 10 ¹⁰ / cm ^2, which is high. The dislocation referred to here is a defect generated during crystal growth, and serves as a non-emission center or causes deterioration of characteristics or life of the light emitting element such as a cause of leakage current.

In order to solve these problems, Japanese Patent Application Laid-Open No. 10-312971 and Japanese Patent Application Laid-Open No.
No. 26912, that is, a mask material is patterned on a substrate and the growth area of gallium nitride is limited to suppress the total number of dislocations generated at the interface between the substrate and gallium nitride. Even in a technique in which gallium nitride is grown on a mask by growth and a GaN substrate having a low dislocation density can be obtained by repeating this process, as shown in FIG. Dislocation line D is bent by the crystal surface C
Dislocations of about 1 × 10 ² / cm ² to 1 × 10 ³ / cm ² exist.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a method of manufacturing a group III nitride semiconductor and a method of manufacturing a semiconductor device which have been made to solve the above-mentioned problems.

[0006] The method for producing a group III nitride semiconductor is as follows.
Forming a first group III nitride semiconductor layer on the substrate by epitaxial growth, removing other portions while leaving a predetermined position on the first group III nitride semiconductor layer, and forming the first group III nitride semiconductor layer by epitaxial growth. 1st left
The second region is removed from the group III nitride semiconductor layer
Forming a group III nitride semiconductor layer by crystal growth, and removing at least the remaining first group III nitride semiconductor layer while leaving a predetermined position of the second group III nitride semiconductor layer. And a step of forming a third group III nitride semiconductor layer by crystal growth in a region removed from the second group III nitride semiconductor layer left by epitaxial growth.

In the above method of manufacturing a group III nitride semiconductor, the first group III nitride semiconductor layer crystal-grown on the substrate has a dislocation. Is removed, and the second group III nitride semiconductor layer is formed in the removed region, so that the second group III nitride semiconductor layer has excellent dislocation-free crystallinity. It becomes a group III nitride semiconductor layer. Further, since at least the remaining first group III nitride semiconductor layer is removed while leaving a predetermined position of the second group III nitride semiconductor layer, the second group III nitride semiconductor layer having no dislocation on the substrate is removed. Only the group III nitride semiconductor layer remains. Then, the third group III nitride semiconductor layer is formed by crystal growth in a region where the first group III nitride semiconductor layer is removed from the second group III nitride semiconductor layer left by the epitaxial growth. In this case, the group III nitride semiconductor layer is formed of the second and third group III nitride semiconductor layers in which dislocations are not generated. In the epitaxial growth of the group III nitride semiconductor, the lateral growth (growth in a direction parallel to the surface of the substrate 11) is better than the vertical growth (growth in a direction perpendicular to the surface of the substrate 11). Is also about 10 times faster, so a new I
It is possible to form a group II nitride semiconductor layer.

[0008] A method of manufacturing a semiconductor device includes a step of forming a first group III nitride semiconductor layer on a substrate by epitaxial growth and a step of forming a first group III nitride semiconductor layer while leaving a predetermined position on the first group III nitride semiconductor layer. Removing the portion, forming a second group III nitride semiconductor layer by crystal growth in the region where the first group III nitride semiconductor layer left by the epitaxial growth has been removed, and forming the second group III nitride semiconductor layer in the second region.
Removing at least the remaining first group III nitride semiconductor layer while leaving a predetermined position of the group III nitride semiconductor layer; and Forming a third group III nitride semiconductor layer by crystal growth in the removed region; and forming a third group III nitride semiconductor layer comprising the second group III nitride semiconductor layer and the third group III nitride semiconductor layer. Forming a semiconductor element on the group III nitride semiconductor layer.

In the method of manufacturing a semiconductor device described above,
As described by the method for manufacturing a group I nitride semiconductor,
Since the group III nitride semiconductor layer including the second and third group III nitride semiconductor layers is formed on the substrate, no dislocation occurs in the group III nitride semiconductor layer. Such II
Since a semiconductor element is formed on the group I nitride semiconductor layer,
The deterioration of the group III nitride semiconductor layer due to the application of a voltage to the semiconductor element is less likely to occur. Therefore, an increase in operating voltage due to use is suppressed, and the life of the semiconductor element is prolonged.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a method of manufacturing a group III nitride semiconductor according to the present invention will be described with reference to a manufacturing process sectional view of FIG.

As shown in FIG. 1A, a first group III nitride semiconductor layer 12 is formed on a substrate 11 by epitaxial growth. The substrate 11 includes aluminum magnesium oxide (MgAl ₂ O ₄ ), silicon oxide (SiO ₂ ), zinc oxide (ZnO), and silicon carbide (S
iC), a substrate made of lithium gallium oxide (LiGaO ₂ ) or aluminum oxide (Al ₂ O ₃ ) is used. The first group III nitride semiconductor layer 12 is made of boron nitride (BN), aluminum nitride (AlN), gallium nitride (GaN), or indium nitride (InN).
Or a mixed crystal of the above-mentioned group III nitride semiconductor, or a crystal formed by combining and selecting from the above-mentioned group III nitride semiconductor and the mixed crystal thereof. As a result, many dislocation lines D are present in first group III nitride semiconductor layer 12 formed by epitaxial growth.

Next, on the surface of the first group III nitride semiconductor layer 12, SiO _x , SiN _x , SiO
A material represented by _1-x N _x , TiO ₂ or ZrO ₂ ,
A resist material composed of an organic material, a resist composed of an inorganic material, or a mask material layer composed of a silylated resist is formed by the following film forming technique suitable for the material. The film forming technology is, for example, a spin coating method,
By a chemical vapor deposition method, a sputtering method, a vapor deposition method, or the like.
Then, the pattern shape of the formed mask material layer is processed into, for example, a stripe shape, a rectangular shape, a circular shape, or a triangular shape as viewed from above the substrate 11 by a lithography technique, so that the first mask 13 is formed. To form

Next, as shown in FIG. 1B, the first group 13 nitride semiconductor layer 12 covered by the first mask 13 is etched by using the first mask 13 as a protective layer. Remove other parts while leaving. In this etching, for example, a normal reactive ion etching apparatus is used, chlorine and hydrogen are used as etching gases, the pressure of the etching atmosphere is 10 Pa, and the substrate temperature is 200 ° C.
I went to set.

When the first group III nitride semiconductor layer 12 is removed by a dry etching process, plasma irradiation of chlorine and hydrogen, methane and hydrogen and argon, argon or oxygen, fluorine, bromine, chlorine Alternatively, an etching gas containing a halogen gas such as iodine and a hydride thereof (that is, hydrogen fluoride, hydrogen bromide, hydrogen chloride, or hydrogen iodide) is used. It is also possible to perform wet etching. As an etching solution in this case, for example, an aqueous solution of potassium hydroxide, aqueous hydrogen peroxide, sulfuric acid or hydrofluoric acid, or a mixture thereof is used.

After that, the first mask 13 is removed. Then, as shown in (3) of FIG. 1, the remaining first III
A group III nitride semiconductor is regrown starting from the group nitride semiconductor layer 12. As a result, from the region A where the dislocation exists at a high density regrown on the first group III nitride semiconductor layer 12 grown first and the first group III nitride semiconductor layer 12 grown first. The second group III nitride semiconductor layer 14 regrown in the lateral direction and in the region B where almost no dislocation is observed is formed.

Next, as shown in FIG.
After forming an organic resist or an inorganic resist so as to protect the second group III nitride semiconductor layer 14,
The second mask 15 is formed by patterning it by, for example, a lithography technique. In this patterning, reference marks (not shown) formed in advance on the substrate 11
Is used to position the pattern. The reference mark is formed by using a metal such as tungsten, aluminum, or copper before or after the growth of the first first group III nitride semiconductor layer 12, or by etching the substrate 11 to form a concave reference mark. Alternatively, a convex reference mark is formed. The design of the fiducial mark is selected from various existing ones according to the fiducial mark reading device.

Next, using the second mask 15 as a protective layer, the second group III nitride semiconductor layer 14 covered by the second mask 15 is left, and other portions are removed by etching. The drawing of (4) shows a state where the second group III nitride semiconductor layer 14 is removed. The etching can be performed by the same etching as the etching described with reference to FIG. After that, the second mask 15 is removed.

Then, as shown in FIG. 1 (5), the group III nitride semiconductor is regrown starting from the remaining second group III nitride semiconductor layer 14. As a result, the second I
A third group III nitride semiconductor layer 16 regrown in the lateral direction from the group II nitride semiconductor layer 14 and having almost no dislocations is formed. In this epitaxial growth,
A group III nitride semiconductor in which dislocations are not observed also grows on the remaining second group III nitride semiconductor layer 14. By repeating the regrowth of the group III nitride semiconductor in this manner, the second, in which dislocations hardly exist on the substrate 11,
The third group III nitride semiconductor layers 14 and 16 can be obtained.

In the above-described method for manufacturing a group III nitride semiconductor, the first group III nitride semiconductor layer 12 grown on the substrate 11 has dislocation lines D.
Since the other portion is removed except for a predetermined position of the group II nitride semiconductor layer 12 and the second group III nitride semiconductor layer 14 is formed in the removed region, the first group III nitride semiconductor is removed. The second group III nitride semiconductor layer 14 grown in the lateral direction of the layer 12 becomes a group III nitride semiconductor layer having no dislocation and excellent crystallinity.

Further, the second group III nitride semiconductor layer 14
Is removed, at least the remaining first group III nitride semiconductor layer 12 is removed.
Only the second group III nitride semiconductor layer 14 in which dislocation has not occurred remains on 1. Then, the first group III nitride semiconductor layer 14 left by the epitaxial growth
Since the third group III nitride semiconductor layer 16 is formed by crystal growth in the region from which the group III nitride semiconductor layer 12 has been removed, the second and third layers having no dislocation on the substrate 11 are formed. III group nitride semiconductor layers 14 and 16
A group nitride semiconductor layer will be formed.

In the epitaxial growth of the group III nitride semiconductor, the growth rate in the lateral direction (growth in the direction parallel to the surface of the substrate 11) is increased in the vertical direction (substrate 1).
Since the growth rate is about 10 times faster than the growth rate in the direction perpendicular to the first plane, a new group III nitride semiconductor layer can be formed in the removed area.

Next, an example of a specific manufacturing method will be described below with reference to FIG.

As shown in FIG. 1A, the substrate 11
As an example, the diameter is 2 inches and the thickness is 300 μm
Aluminum oxide (Al ₂ ) having a crystal orientation of (0001)
O ₃ ) A substrate is used. The substrate 11 has a metal organic chemical vapor (MOCVD).
A buffer layer (not shown) made of, for example, aluminum nitride (AlN) having a thickness of 30 nm is formed by using an or deposition apparatus. Next, gallium nitride (GaN) is grown to a thickness of, for example, 1.5 μm at 1100 ° C. using an MOCVD apparatus to form a first group III nitride semiconductor layer 12. It is preferable that the buffer layer and the first group III nitride semiconductor layer 12 are continuously formed by a MOCVD apparatus. The conditions for forming the first group III nitride semiconductor layer 12 are, for example, as follows. Ammonia (NH ₃ ) and tetramethylgallium (TMGa) are used as source gases, The temperature was set at 1000 ° C.

Further, for example, an SiO ₂ film having a thickness of 100 nm is deposited as a mask material layer on the surface of the first group III nitride semiconductor layer 12 by, for example, sputtering. Thereafter, the mask material layer is processed into a striped pattern having a line width of 5 μm and a pitch of 15 μm by a lithography technique and an etching technique, thereby forming the first mask 1.
Form 3

Further, as shown in FIG. 1B, a portion of the first group 13 which is not covered with the first mask 13 is dry-etched using, for example, chlorine and hydrogen as an etching gas. Object semiconductor layer 12 to substrate 1
1 to remove the surface by etching. After that, the first mask 13 is removed by wet etching using, for example, hydrofluoric acid.

Then, as shown in FIG. 1 (3), the group III nitride semiconductor is re-grown from the remaining first group III nitride semiconductor layer 12 as a starting point, so that the first group III nitride semiconductor that has grown first is grown.
Region A in which high-density dislocations are regrown on the group III nitride semiconductor layer 12 of FIG.
A flat second III in region B where almost no dislocation is regrown in the lateral direction from group II nitride semiconductor layer 12
A group nitride semiconductor layer 14 is formed. The second III
The conditions for forming the group-III nitride semiconductor layer 14 are, for example, as follows.
Ammonia (NH ₃ ) and tetramethylgallium (TMGa) were used as source gases, the pressure of the film formation atmosphere was set to normal pressure, and the substrate temperature was set to 1000 ° C.

Next, as shown in FIG. 1D, the second group III nitride semiconductor layer 14 is formed by sputtering.
The SiO ₂ film is, for example, 100
After being deposited to a thickness of nm, the second mask 15 is formed by, for example, a lithography technique and an etching technique into a stripe pattern having a line width of 5 μm and a pitch of 15 μm.

In this patterning, the mask is positioned using predetermined reference marks (not shown) made of tungsten at predetermined positions on the substrate 11, for example, at the four corners, and the second group III nitride film is formed. A second mask 15 having the above-mentioned striped pattern is formed so as to protect a region of the semiconductor layer 14 where dislocations are not observed.

Next, using the second mask 15 as a protective layer, the second group III nitride semiconductor layer 14 covered by the second mask 15 is left, and other portions are removed by etching. For this etching, the same etching as that described with reference to FIG. 1B can be used. After that, the second mask 15 is removed using, for example, hydrofluoric acid.

Then, as shown in FIG. 1 (5), the group III nitride semiconductor is regrown with the remaining second group III nitride semiconductor layer 14 as a starting point. As a result, the second I
A third group III nitride semiconductor layer 16 regrown in the lateral direction from the group II nitride semiconductor layer 14 and having almost no dislocations is formed. In this epitaxial growth,
A group III nitride semiconductor in which dislocations are not observed also grows on the remaining second group III nitride semiconductor layer 14. By repeating the regrowth of the group III nitride semiconductor in this manner, it is possible to obtain the third group III nitride semiconductor layer 16 having almost no dislocation on the substrate 11. Conditions for forming the third group III nitride semiconductor layer 16 are as follows:
As an example, ammonia (NH ₃ ) and tetramethylgallium (TMGa) were used as source gases, the pressure of the film formation atmosphere was set to normal pressure, and the substrate temperature was set to 1000 ° C.

The first and second masks 13 and 15 may be made of polymethyl methacrylate (PMMA). In this case, the thickness is set to 1 μm, for example, by a spin coating method.
After the application of MMA, it is formed into a striped pattern by a lithography technique, thereby forming first and second masks. The removal of PMMA is performed by oxygen plasma irradiation.

Furthermore, a silylated resist may be used for the first and second masks 13 and 15. In this case, a silylated resist is applied to a thickness of, for example, 300 nm by a spin coating method, silylated with a silylating agent, and then etched with oxygen plasma to form a striped pattern. The second masks 13 and 15 are used. Removal of the silylated resist is performed using tetrafluoromethane (C
F ₄ ) is performed by plasma irradiation.

In the above embodiment, the case where gallium nitride is used as the group III nitride semiconductor has been described. However, the group III nitride semiconductor can be formed of boron nitride, aluminum nitride or indium nitride. As an example of the conditions for forming the boron nitride film, ammonia (NH ₃ ) and tetramethylboron (TMB) are used as source gases, the pressure of the film formation atmosphere is set to normal pressure, and the substrate temperature is set to 1200 ° C. The conditions for forming the aluminum nitride film are, for example, as follows: ammonia (NH ₃ ) and tetramethylaluminum (TMAl) are used as source gases, the pressure of the film formation atmosphere is normal pressure, and the substrate temperature is 1100 ° C. .
The conditions for forming the indium nitride film are, for example, as follows: ammonia (NH ₃ ) and tetramethylindium (TMIn) are used as source gases, the pressure of the film formation atmosphere is normal pressure, and the substrate temperature is 900 ° C. . In addition, the first to third
The group III nitride semiconductor layers 12, 14, 16 may be made of a combination of plural kinds of boron nitride, aluminum nitride, gallium nitride, and indium nitride. Alternatively, it may be made of a mixed crystal of a plurality of kinds of boron nitride, aluminum nitride, gallium nitride, and indium nitride. Alternatively, it may be composed of a combination of a plurality of kinds of the mixed crystal, boron nitride, aluminum nitride, gallium nitride and indium nitride.

The apparatus for forming the first to third group III nitride semiconductor layers 12, 14, 16 is MOCVD.
In addition to the equipment, metal organic vapor phase epitaxial growth (MOV
PE: Metal Organic Vapor Phase Epitaxial growth)
Equipment, vapor phase epitaxial growth (eg, HVPE: Hy
dride Vapor Phase Epitaxial growth equipment, Molecular Beam Epitaxial Growth (MBE)
growth) It is also possible to use a device or the like.

Further, in the above-mentioned etching of boron nitride, for example, a usual reactive ion etching apparatus is used, and the etching gas is oxygen-excess oxygen (O ₂ ).
Using a mixed gas of methane and tetrafluoromethane (CF ₄ ), the pressure of the etching atmosphere is 10.6 Pa, the substrate temperature is room temperature, and the magnetically enhanced RIE (Reactive Ion Etchi
ng) method. Alternatively, it can be performed by chemical etching in a hydrogen atmosphere containing 1% methane (CH ₄ ) heated indirectly by a carbide-coated tungsten filament at 2000 ° C. For etching of aluminum nitride or indium nitride, for example, a normal reactive ion etching apparatus is used, a mixed gas of hydrogen (H ₂ ) and chlorine (Cl ₂ ) is used as an etching gas, and the pressure of the etching atmosphere is reduced. 10 Pa, substrate temperature 2
The setting was performed at 00 ° C.

Next, as an example of an embodiment of a method of manufacturing a semiconductor device according to the present invention, a group III nitride semiconductor layer is formed by using the method of manufacturing a group III nitride semiconductor, and
A manufacturing method for forming a semiconductor light emitting device will be described below with reference to a manufacturing process sectional view of FIG.

As shown in FIG. 2A, the method for manufacturing a group III nitride semiconductor described with reference to FIG.
A group III nitride semiconductor layer 21 made of gallium nitride (GaN) is formed on a substrate 11. Then, for example, MOCV
By the D method, on the group III nitride semiconductor layer 21,
An n-side contact layer 22 made of n-type gallium nitride (n-type GaN) and an n-type gallium aluminum nitride (n-type A
1GaN), a first guide layer 24 made of n-type gallium nitride (n-type GaN), and an active layer 2 made of indium gallium nitride (GaInN).
5. Deterioration prevention layer 26, p-type gallium nitride (p-type Ga
N), a p-side cladding layer 28 made of p-type gallium aluminum nitride (p-type AlGaN), and a p-type gallium nitride (p-type GaN)
The side contact layer 29 is formed sequentially.

In the MOCVD method, the substrate temperature is set to 800
To 1000 ° C., a trimethylaluminum (Al (CH ₃ ) ₃ ) gas as a source gas of aluminum, and a trimethylgallium (Ga (CH ₃ )) gas as a source gas of gallium.
₃₎ gas, nitrogen (a raw material gas for N ₂₎ Ammonia (N
Monosilane (Si) is used as H ₃ ) gas and silicon source gas.
H ₄ ) gas is used. Each of the semiconductor layers of the n-side contact layer 22 to the p-side contact layer 29 has I
Since no dislocation exists in the group II nitride semiconductor layer 21, no dislocation occurs.

After the respective semiconductor layers of the n-side contact layer 22 to the p-side contact layer 29 are formed, an insulating layer 30 made of SiO ₂ is formed on the p-side contact layer 29 by, for example, a CVD method. Next, after forming a resist film (not shown) on the insulating layer 30 by, for example, a coating method, the resist film is patterned by a lithography technique,
An opening is formed on the position where the p-side electrode is to be formed. Using the resist mask as an etching mask, the insulating layer 3
An opening 31 is formed at 0.

Subsequently, the above resist mask (not shown)
After, for example, nickel and gold are sequentially vapor-deposited on the upper portion and the opening 31, the resist mask and the nickel and gold formed on the resist mask are both removed by a lift-off method. As a result, a p-side electrode 32 is formed in the opening 31.

Next, as shown in FIG. 2B, after an etching mask (not shown) is formed on the p-side electrode 32 and the insulating layer 30 around the p-side electrode 32 by a usual resist coating and lithography technique. By the etching technique using the etching mask, the insulating layer 30 and the p-side contact layer 29 corresponding to the formation position of the n-side electrode are formed.
To the n-side cladding layer 23 are sequentially and selectively removed. After that, the etching mask is removed. Then, on the n-side contact layer 22, titanium, aluminum and gold are selectively vapor-deposited sequentially to form the n-side electrode 3.
Form 3 In the drawing of (2), the state in which the n-side electrode 33 is formed is shown.

Next, the substrate 11 is cleaved with a predetermined width perpendicular to the length direction of the p-side electrode 32 (resonator length direction), and a reflection mirror layer (not shown) is formed on the cleavage surface (not shown). Form. Thus, the semiconductor light emitting device 20 is formed.

In the semiconductor light emitting device 20, the n-side electrode 3
When a predetermined voltage is applied between 3 and the p-side electrode 32,
A current is injected into the active layer 25, and light emission occurs due to electron-hole recombination. In the above configuration, the dislocation density of the group III nitride semiconductor layer 21 formed between the substrate 11 and the semiconductor layer including the n-side contact layer 22 to the p-side contact layer 29 is low. Deterioration is less likely to occur. Therefore, an increase in operating voltage due to use is suppressed, and the life of the semiconductor light emitting element 20 is prolonged.

[0044]

As described above, according to the method for manufacturing a group III nitride semiconductor of the present invention, the crystal is formed in the layer direction, that is, in the so-called lateral direction, from the group III nitride semiconductor layer in which dislocation has occurred to the substrate surface. Utilizing that a group III nitride semiconductor layer in which dislocations do not occur when grown is used to form a first group III nitride semiconductor layer in which dislocations have occurred in a substrate, a part of which is removed, and then A second group III nitride semiconductor layer that does not generate dislocations is formed by crystal growth in the removed region, and then the first group III nitride semiconductor layer that has generated dislocations is completely removed and removed. Since the third group III nitride semiconductor layer in which dislocations do not occur in the region is formed by crystal growth, the third and third group III nitride semiconductor layers in which no dislocations occur on the substrate are formed of group III nitride semiconductor layers. Form nitride semiconductor layer Rukoto can.

According to the method of manufacturing a semiconductor device of the present invention,
By removing a part of the first group III nitride semiconductor layer in which dislocation has occurred and forming second and third group III nitride semiconductor layers in which no dislocation has occurred in the removed region, the whole Since a group III nitride semiconductor layer having no dislocation is formed and a semiconductor element is formed on the group III nitride semiconductor layer, it is possible to suppress deterioration of the group III nitride semiconductor layer due to application of a voltage to the semiconductor element. Can be. Therefore, an increase in operating voltage due to use can be suppressed, and the life of the semiconductor element can be extended.

[Brief description of the drawings]

FIG. 1 is a manufacturing process sectional view showing an example of an embodiment according to a method for manufacturing a group III nitride semiconductor of the present invention.

FIG. 2 is a cross-sectional view of a manufacturing process showing one example of an embodiment relating to a method of manufacturing a semiconductor device of the present invention.

FIG. 3 is an explanatory diagram of a problem.

[Explanation of symbols]

11: substrate, 12: first group III nitride semiconductor layer, 1
4: second III group nitride semiconductor layer; 16: third II
Crystal growth of group I nitride semiconductor layer

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) DB02 5F052 GB01 GB04 GB09 GC01 GC06 GC10 HA01 JA10 KA01 5F073 AA45 CA07 CB05 CB10 DA05 DA25 EA28 EA29

Claims (10)

[Claims] A step of forming a first group III nitride semiconductor layer on a substrate by epitaxial growth; and a step of removing another part of the first group III nitride semiconductor layer while leaving a predetermined position. Forming a second group III nitride semiconductor layer in a region removed from the remaining first group III nitride semiconductor layer by epitaxial growth; and a predetermined position of the second group III nitride semiconductor layer. Removing at least the remaining first group III nitride semiconductor layer while leaving a third group III nitride in a region removed from the remaining second group III nitride semiconductor layer by epitaxial growth Forming a semiconductor layer. 2. The manufacturing method according to claim 1, wherein the first to third group III nitride semiconductor layers are made of boron nitride, aluminum nitride, gallium nitride or indium nitride. Method. 3. The semiconductor device according to claim 1, wherein the first to third group III nitride semiconductor layers are made of a combination of plural kinds of boron nitride, aluminum nitride, gallium nitride and indium nitride. A method for producing a group III nitride semiconductor. 4. The semiconductor device according to claim 1, wherein the first to third group III nitride semiconductor layers are made of a mixed crystal of a plurality of kinds of boron nitride, aluminum nitride, gallium nitride, and indium nitride. A method for producing a group III nitride semiconductor according to the above. 5. The semiconductor device according to claim 1, wherein the first to third group III nitride semiconductor layers are made of a combination of a plurality of kinds of the mixed crystal, boron nitride, aluminum nitride, gallium nitride, and indium nitride. Item 6. The method for producing a group III nitride semiconductor according to item 4. 6. A step of forming a first group III nitride semiconductor layer on a substrate by epitaxial growth, and a step of removing another part of the first group III nitride semiconductor layer while keeping a predetermined position. Forming a second group III nitride semiconductor layer in a region removed from the remaining first group III nitride semiconductor layer by epitaxial growth; and a predetermined position of the second group III nitride semiconductor layer. Removing at least the remaining first group III nitride semiconductor layer while leaving a third group III nitride in a region removed from the remaining second group III nitride semiconductor layer by epitaxial growth Forming a semiconductor layer, the second group III nitride semiconductor layer and the third III
Forming a semiconductor element on the group-III nitride semiconductor layer composed of the group-III nitride semiconductor layer. 7. The method according to claim 6, wherein the first to third group III nitride semiconductor layers are made of boron nitride, aluminum nitride, gallium nitride, or indium nitride. 8. The semiconductor device according to claim 6, wherein the first to third group III nitride semiconductor layers are made of a combination of boron nitride, aluminum nitride, gallium nitride and indium nitride. A method for manufacturing a semiconductor device. 9. The semiconductor device according to claim 6, wherein said first to third group III nitride semiconductor layers are made of a mixed crystal of a plurality of kinds of boron nitride, aluminum nitride, gallium nitride and indium nitride. Of manufacturing a semiconductor device. 10. The first to third group III nitride semiconductor layers are made of a combination of plural kinds of the mixed crystal, boron nitride, aluminum nitride, gallium nitride and indium nitride. Item 7. A method for manufacturing a semiconductor device according to Item 6.