JP2001274518A - Substrate for semiconductor element, method for manufacturing the same and semiconductor element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a flat substrate for a semiconductor element with less defects by simple processes. SOLUTION: An AlN buffer layer 12 is formed with the film thickness of about 20 nm at a temperature 500 deg.C on a 6H-SiC substrate 11, then the temperature is turned to 1050 deg.C and a GaN layer 13 is grown for about 3 μm. Thereafter, an SiO2 film 14 is formed and resist 15 is applied. Then, a stripe area where the SiO2 film 14 of the width of 5 μm is removed is formed with the interval of about 25 μm, it is turned to a mask, the GaN layer 13 is removed for the depth of about 3 μm by dry etching and rectangular groove stripes are formed. After removing the resist 15 and the SiO2 film 14, when heat treatment is performed at 1050 deg.C by nitrogen and ammonia gas atmosphere, a low-defect GaN layer 16 is formed at the groove part by a mass transport phenomenon. Thereafter, with the resist 18 and the SiO2 film 17 as the mask, the GaN layer 13 to the upper surface of the SiC substrate 11 or a part is removed by dry etching by using chlorine-based gas. Thereafter, the resist 18 and the SiO2 film 17 are removed. Then, the GaN layer 19 is selectively grown for about 10 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device substrate, a method of manufacturing the same, a semiconductor device and a semiconductor laser device using the semiconductor device substrate, and in particular, it is difficult to manufacture a substrate having a low defect density. The present invention relates to a semiconductor element substrate made of a group III nitrogen compound, a method of manufacturing the same, and a semiconductor element and a semiconductor laser device using the semiconductor element substrate.

[0002]

2. Description of the Related Art As a short-wavelength semiconductor laser device in the 410 nm band, Jpn.Appl.phys.Vol.38.pp.L226-L issued in 1999.
At 229, after GaN is formed on the sapphire substrate, Ga is formed by selective growth using SiO2 as a mask.
After N is formed, the sapphire substrate is peeled off and the n-GaN buffer layer, the n-InGaN crack preventing layer, the n-AlGaN / GaN modulation-doped superlattice cladding layer, the n-GaN optical waveguide layer, and the n-GaN InGaN / InG
aN multiple quantum well active layer, p-AlGaN carrier block layer, p-GaN optical waveguide layer, p-AlGaN / GaN
A layer formed by laminating a modulation-doped superlattice cladding layer and a p-GaN contact layer has been reported. However,
This semiconductor laser still has a high defect density and has not been able to obtain high output reliability.

Therefore, as a method of manufacturing a low defect substrate used for these semiconductor lasers, Ext.
str. (MRS Fall Meet.Boston) G3.38, TSZhele
Pendeo-Epitaxy-A New Approach for La by va et al.
Teral Growth of Gallium Nitride Structures is introduced. Here, without masking SiO2, GaN
After forming GaN, it is reported that a flat film is formed by removing GaN in a stripe shape to the sapphire substrate and growing GaN on the substrate, utilizing the lateral growth of GaN. ing. Also, using this method, in SPIE Vol.3628.pp.158 issued in 1999,
Although it has been reported that an InGaN multiple quantum well semiconductor laser device can be produced, the reliability is limited to a level of 5 mW, and the defect density needs to be further reduced.

[0004] Furthermore, Nitta et al., Described on page 281, p. W-11, in Proceedings of the 60th Annual Meeting of the Japan Society of Applied Physics 1999, "Reduction of threading dislocation density in GaN by mass transport." ”Shows that Ga stacked on a sapphire substrate
It has been reported that when a periodic groove structure is formed in an N layer and heat treatment is performed in a nitrogen and ammonia atmosphere at 1000 ° C., a region having few defects is formed in the groove by mass transport. However, application to device fabrication requires a reduction in defect density over a larger area than described above.

In Japanese Patent Application Laid-Open No. 10-312971, Ga
As a method of suppressing cracks caused by the difference in thermal expansion and lattice constant between the N compound semiconductor layer and the sapphire substrate crystal and suppressing the introduction of defects, a growth region is limited by a mask, and a facet structure of a GaN compound semiconductor film is formed by epitaxial growth. Then, a crystal growth method has been reported in which a facet structure is completely buried until the mask is covered, and finally a flat surface is obtained. In this method, since the entire base of the seed growth region is grown on a substrate with a large lattice mismatch, the crystal orientation that grows in the lateral direction changes due to the influence of the substrate, and planarization is also difficult, Even if this method is repeated, there is a difference in the plane orientation, so that the defect cannot be reduced to a practical level.

[0006]

As described above, especially in a semiconductor laser device having a short wavelength, there are many problems in the reliability under a high output because the substrate has many crystal defects.

In view of the above circumstances, it is an object of the present invention to provide a highly reliable semiconductor element substrate having a low defect density, a method of manufacturing the same, and a semiconductor element and a semiconductor laser device using the semiconductor element substrate. It is assumed that.

[0008]

According to a method of manufacturing a substrate for a semiconductor device of the present invention, a first group III nitrogen compound is formed on a base substrate via a buffer layer of AlN or GaN formed by a low-temperature growth method. A first step of growing a crystal of the layer, a second step of patterning the first group III nitrogen compound layer in an uneven shape, and a heat treatment in a nitrogen and ammonia atmosphere to form a second group III nitrogen compound inside the recess. A third step of forming a layer; a second group III nitrogen compound layer;
A fourth step of removing the first group III nitrogen compound layer and the buffer layer to the substrate so as to leave the first group III nitrogen compound layer and the buffer layer below the group II nitrogen compound layer; Second group III nitrogen compound layer, first III
A fifth step of using the group III nitrogen compound layer and the buffer layer as nuclei for crystal growth and growing a third group III nitrogen compound layer until the surface is flattened.

[0009] After the fifth step, on the third group III nitrogen compound layer corresponding to the upper part of the second group III nitrogen compound layer, at least the width of the second group III nitrogen compound layer is equal to
Forming a mask layer made of a material in which the group III nitrogen compound cannot grow crystals, and using the surface of the third group III nitrogen compound layer on which the mask layer is not formed as a nucleus for crystal growth of the group III nitrogen compound; A sixth step of growing the group-nitrogen compound layer until the surface is flattened may be performed.

[0010] After the sixth step, above the group III nitrogen compound layer formed in the immediately preceding step and above the space portion between the mask layers formed immediately before the group III nitrogen compound layer. Then, a mask layer made of a material in which the group III nitrogen compound cannot grow crystal is formed, and the mask layer is not formed.
The step of growing the group III nitrogen compound layer until the surface is flattened may be performed one or more times using the surface of the group I nitrogen compound as a nucleus for crystal growth of the group III nitrogen compound.

Each group III nitrogen compound layer may be formed while doping with conductive impurities.

After the last of the above steps, the base substrate may be removed.

The base substrate is made of sapphire, Si
C, ZnO, LiGaO2, LiAlO2, GaAs,
It is desirably any one selected from the group consisting of GaP, Ge and Si.

The buffer layer and each group III nitrogen compound layer are formed by HVPE (hydride vapor phase epitaxy) or MOCVD (metal organic chemical vapor deposition).
On) method is desirable.

The group III nitrogen compound layer is made of GaN, InGa
N, AlGaN, InAlGaN, InAlN and I
Desirably, it consists of one selected from the group consisting of nN.

A semiconductor device substrate according to the present invention is manufactured by the method for manufacturing a semiconductor device substrate according to the present invention having the above-described structure.

A semiconductor device according to the present invention is characterized in that a semiconductor layer is provided on a substrate for a semiconductor device manufactured by the method for manufacturing a substrate for a semiconductor device according to the present invention having the above configuration.

A semiconductor laser device according to the present invention comprises a semiconductor layer on a semiconductor element substrate manufactured by the method for manufacturing a semiconductor element substrate according to the present invention having the above-described structure, and a current formed on the semiconductor layer. The width of a stripe serving as an injection window is 1 μm or more.

[0019]

According to the method of manufacturing a semiconductor device substrate of the present invention, a first group III nitrogen compound layer is grown on a base substrate via a buffer layer formed by a low-temperature growth method. After patterning the group III nitrogen compound layer of the unevenness, heat treatment with nitrogen and ammonia causes a mass transport phenomenon, and a low-defect second group III nitrogen compound layer is formed inside the concave portion. Leaving the second group III nitrogen compound layer formed inside the recess and the first group III nitrogen compound layer and the buffer layer thereunder, using it as a nucleus for crystal growth, and growing the third group by lateral growth. By forming the group III nitrogen compound layer of the above, a substrate of a group III nitrogen compound with low defect can be formed. That is, since the low-defect second group III nitrogen compound layer inside the recess formed by the mass transport phenomenon is used as a nucleus for crystal growth, a low-defect group III nitrogen compound substrate can be obtained.

In the method of manufacturing a substrate for a semiconductor device according to the present invention, a mask layer is further formed on the group III nitrogen compound layer formed inside the recess and on the third group III nitrogen compound. A third group III nitrogen compound exposed between the mask layers is used as a nucleus for crystal growth, and a group III nitrogen compound is selectively grown in a lateral direction to obtain a flat group III nitrogen compound layer without defects. be able to.

Furthermore, a mask layer is further formed on the group III nitrogen compound layer formed in the immediately preceding step and on the space portion of the mask layer formed immediately before the group III nitrogen compound layer, By repeating the step of selectively growing a group III nitrogen compound using the group III nitrogen compound layer exposed at a place where the mask layer is not formed as a nucleus for crystal growth, defects can be reduced in each step, Finally, a completely defect-free substrate can be obtained.

Further, a conductive substrate can be manufactured by doping a conductive impurity when crystal growing a layer of a group III nitrogen compound.

Further, after the last step, the base substrate may be removed, and there is no problem in reliability.

Further, according to the semiconductor device of the present invention, since the semiconductor layer is provided on the semiconductor device substrate of the present invention having few defects, the reliability can be improved.

According to the semiconductor laser device of the present invention, a semiconductor layer is provided on the semiconductor element substrate of the present invention, and the width of a stripe serving as a current injection window formed in the semiconductor layer is 1 μm or more. By virtue of this, the oscillation region can be formed on the region having a low defect, so that high reliability up to high output can be obtained.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings.

A method of manufacturing a semiconductor device substrate according to the first embodiment of the present invention will be described. FIG. 1 shows a process of manufacturing the semiconductor device substrate. Trimethylgallium (TM
G), trimethylaluminum (TMA), trimethylindium (TMI) and ammonia as raw materials for growth, silane gas as n-type dopant gas, and cyclopentadienyl magnesium (Cp ₂ Mg) as p-type dopant
Is used.

Next, as shown in FIG. 1A, the metal film is grown on a (0001) 6H-SiC substrate 11 at a temperature of 500
An AlN buffer layer 12 is formed at a temperature of about 20 nm.
Subsequently, the temperature is set to 1050 ° C., and the GaN layer 13 is grown to about 3 μm. After that, an SiO ₂ film 14 is formed, and after applying a resist 15,
Using normal lithography,

[0029]

[Formula 1] 5 so as to leave a 25 μm wide SiO ₂ film 14 and resist 15
Line and space patterns are formed at intervals of about μm.

Next, as shown in FIG.
Using the SiO ₂ film 14 as a mask, a GaN layer 1
3 is removed by about 3 μm in depth by dry etching to form a rectangular groove stripe. After that, resist 15 and Si
The O ₂ film 14 is removed.

Next, as shown in FIG. 1C, when heat treatment is performed at 1050 ° C. in an atmosphere of nitrogen and ammonia gas, a mass transport phenomenon occurs and the GaN layer 16 is formed in the groove.
The heat treatment is performed until the groove is almost filled. Since the lateral growth from the groove side surface is dominant in forming the GaN layer 16, the GaN layer 16 having a low defect density is formed. Here, the mass transport phenomenon means that some of the constituent elements of a substance formed on a certain substrate move by evaporation or surface migration, and a part of the element has crystallinity at another part of the same substrate. A phenomenon that is formed by

After that, as shown in FIG. 1D, an SiO ₂ film 17 is formed, a resist 18 is applied, and then a usual lithography

[0033]

[Formula 2] In the direction, the resist 18 and the SiO ₂ film 17 are removed from the region other than the region extending from the end of the GaN layer 16 formed in the groove toward the inside of the groove by about 1 μm toward the inside of the groove.

Next, as shown in FIG.
Using the SiO ₂ film 17 as a mask, the GaN layer 13 and the buffer layer 12 are dry-etched using a chlorine-based gas to form the SiC substrate 11.
Up to or part of the top surface. Then resist
18 and the SiO ₂ film 17 are removed.

Next, as shown in FIG.
Selectively grow about μm. At this time, the GaN layer 19 does not adhere to the substrate 11, but the stripes are finally combined by the lateral crystal growth and the surface is flattened, thereby completing the semiconductor element substrate.

On the semiconductor element substrate thus manufactured,
GaN-based semiconductor layers (for example, GaN, InGaN, AlGaN, InGaAlN
, Etc.) to produce a semiconductor light emitting element and an electronic device.

The substrate 11 may be a (0001) plane 4H-SiC substrate.

Further, a GaN layer is further grown to a thickness of about 100 to 200 μm on the semiconductor device substrate prepared above, and after removing the SiC substrate, a GaN-based semiconductor layer (for example, GaN, InGaN, AlGaN,
A semiconductor light emitting element and an electronic device can also be manufactured by crystal growth of InGaAlN).

Next, a description will be given of a semiconductor device substrate according to a second embodiment of the present invention, and a cross-sectional view thereof is shown in FIG. Since the present invention is the same up to the last step of the first embodiment, the same elements are denoted by the same reference numerals and description thereof will be omitted.

On the substrate formed up to the step of FIG. 1f in the first embodiment, the GaN layer 19
A mask layer 20 is formed on the GaN layer 16 left in the form of a line so as to have a width of about 2 μm from each end of the GaN layer 16. next,
At a temperature of 1050 ° C., the GaN layer 21 is selectively grown to about 20 μm. This masks some defects existing above the linear GaN layer 16, so that the selectively grown Ga
The surface of the N layer 21 can be further reduced in defect.

Further, on the GaN layer 21, the mask layer 2
A mask layer is formed above the region where 0 is not formed, and the exposed portion of the GaN layer 21 is used as a crystal growth nucleus to perform crystal growth of GaN one or more times. Thus, a GaN substrate having almost no defects can be manufactured.

As shown in FIG. 3, the SiC substrate may be removed after a desired number of steps of forming a mask layer and crystal-growing a GaN layer.

In the first and second embodiments, Ga
The method of fabricating the N substrate was described, but AlGaN, InGaN, InA
These substrates can be manufactured by crystal growth of lGaN, InAlN or InN.

In the above two embodiments, the case of undoped GaN growth has been described. However, by introducing a conductive impurity during the growth of GaN, n or p-type Ga is grown.
N conductive substrate can be manufactured. At this time, for example, a heat treatment may be performed in a nitrogen atmosphere after the growth or a growth may be performed in a nitrogen-rich atmosphere to activate the p-type impurity Mg. Also, after forming a conductive substrate, after laminating a semiconductor layer such as an active layer on the substrate, removing the substrate as shown in FIG. 3, and further removing the buffer layer, an electrode is formed on the back surface. And the element manufacturing process can be simplified.

In addition, gallium (G) is used for crystal growth of the GaN layer.
a) A growth method using a hydride VPE method using GaCl, which is a reaction product of hydrogen chloride (HCl), and ammonia (NH ₃ ) may be used.

In the above two embodiments, the case where the SiC substrate is used has been described.
It can be formed on a substrate of O, LiGaO ₂ , LiAlO ₂ , ZnSe, GaAs, GaP, Ge, Si or the like by the same method.

As a mask material, in addition to the above-mentioned SiO ₂ ,
A mask material such as SiN, AlN, or TiN having good heat resistance at high temperatures may be used.

Next, a description will be given of a semiconductor laser device according to a third embodiment of the present invention, and a sectional view of the semiconductor laser device is shown in FIG. The substrate of the semiconductor laser device according to the first embodiment is used as the substrate of the semiconductor laser device, and the same reference numerals are given to the respective components, and the description is omitted. As shown in FIG.
On the layer 19, an n-GaN contact layer 31, 150 pairs of n-Al _0.14
Ga _0.86 N (2.5 nm) / GaN (2.5 nm) superlattice cladding layer 3
2, n-GaN optical waveguide layer 33, n-In _0.02 Ga _0.98 N (10.5 nm) / I
n _0.15 Ga _0.85 N (3.5 nm) triple quantum well active layer 34, p-Al
_0.2 Ga _0.8 N carrier block layer 35, p-GaN optical waveguide layer 36, 1
50 pairs of p-Al _0.14 Ga _0.86 N (2.5 nm) / GaN (2.5 nm)
A superlattice cladding layer 37 and a p-GaN contact layer 38 are stacked. For activation of the p-type impurity Mg, either a heat treatment may be performed in a nitrogen atmosphere after the growth or a growth may be performed in a nitrogen-rich atmosphere.

Subsequently, an SiO ₂ film (not shown) and a resist (not shown) are formed, and are formed by ordinary lithography.
Resist and SiO _{2 in a} stripe region with a width of 1-2 μm
The SiO ₂ film and the resist are removed except for this region so that the film remains. P-Al _0.14 Ga _0.86 N (2.5 nm) / GaN (2.5 nm) by selective etching with RIE (Reactive Ion Etching Equipment)
nm) Etching is performed partway through the superlattice cladding layer 37. P-Al _0.14 Ga _0.86 N (2.5 nm) / Ga
The remaining thickness of the N (2.5 nm) superlattice cladding layer 37 is a thickness at which fundamental transverse mode oscillation can be achieved. Then, with resist
The SiO ₂ film is removed.

Subsequently, an SiO ₂ film (not shown) and a resist (not shown) are formed, and the SiO ₂ film and the resist are removed except for the stripe region and a region including a region 50 μm outside each end of the stripe region. Etching is performed by RIE until the n-GaN contact layer 31 is exposed. Thereafter, using an ordinary lithography technique, an insulating film 39, an n-electrode 41 of Ti / Au,
A p-electrode 40 of Ni / Au is formed on the surface of the mold contact layer 38 in a stripe shape. Thereafter, the substrate surface is polished, and the sample is cleaved to form a resonator surface, which is coated with a high reflectance coating and a non-reflection coating, and then formed into chips to form a semiconductor laser device.

In the semiconductor laser device according to the present embodiment, since a stripe is formed on a substrate having a low defect, stable fundamental transverse mode oscillation can be obtained.

Next, a semiconductor laser device according to a fourth embodiment of the present invention will be described, and a cross-sectional view thereof is shown in FIG. The substrate of this semiconductor laser device is the same up to the formation of the SiO ₂ film 20 of the substrate for a semiconductor device according to the second embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted. FIG.
As shown in FIG. 3, the SiO ₂ film 20 formed in the second embodiment
An n-GaN contact layer 50 is crystal-grown thereon. Subsequently, 150 pairs of n-Al _0.14 Ga _0.86 N (2.5 nm) / GaN (2.5 nm)
nm) Superlattice cladding layer 51, n-GaN optical waveguide layer 52, n-In
_0.02 Ga _0.98 N (10.5 nm) / In _0.15 Ga _0.85 N (3.5 nm) 3
Quantum well active layer _{53, p-Al 0.2 Ga 0.8} N of the carrier block layer 54, p-GaN optical waveguide layer 55,150 pairs p-Al _{0. 14} Ga _0.86 N
(2.5 nm) / GaN (2.5 nm) superlattice cladding layer 56, p-G
The aN contact layer 57 is laminated. In order to activate the p-type impurity Mg, any method of performing heat treatment in a nitrogen atmosphere after growth or performing growth in a nitrogen-rich atmosphere may be used.

Subsequently, an SiO ₂ film (not shown) and a resist (not shown) are formed, and 1.
So that only the stripe region with a width of ~ 2 μm remains
The resist and the SiO ₂ film are removed. P-Al _0.14 Ga _0.86 N by selective etching with RIE (Reactive Ion Etching Equipment)
(2.5 nm) / GaN (2.5 nm) The etching is performed halfway through the superlattice cladding layer 56. P-Al _0.14 Ga of this etching
_0.86 N (2.5 nm) / GaN (2.5 nm) superlattice cladding layer 56
Is a thickness at which fundamental transverse mode oscillation can be achieved.

After that, the resist and the SiO ₂ film are removed, and subsequently, an SiO ₂ film (not shown) and a resist (not shown) are formed, except for the region where the stripe exists and the region 50 μm outside each end of the stripe. The resist and the SiO ₂ film are removed, and etching is performed by RIE until the n-GaN contact layer 50 is exposed. Thereafter, an insulating film 58, an n-electrode 60 made of Ti / Au, and a p-electrode 59 made of Ni / Au are formed on the surface of the p-type contact layer in stripes by using a usual lithography technique. Thereafter, the substrate surface is polished, and the sample is cleaved to form a resonator surface, which is coated with a high reflectance coating and a non-reflection coating, and then formed into chips to form a semiconductor laser device.

With respect to the wavelength λ at which the semiconductor laser devices according to the third and fourth embodiments oscillate, In _x4 Ga
_{By using 1-x4} N as an active layer and setting the composition to 0 ≦ x4 ≦ 0.5, control can be performed in the range of 360 ≦ λ ≦ 550 (nm).
In the third and fourth embodiments, the conductivity of each semiconductor layer may be inverted (the n-type and the p-type are interchanged).

In the third and fourth embodiments,
Although a semiconductor laser device that oscillates in a fundamental mode with a narrow stripe has been described, a high-power semiconductor laser device with a wide stripe can be manufactured by setting the stripe width to 2 μm or more.

Also, the semiconductor device substrate of the present invention may be replaced with an AlGaN-based short-wavelength semiconductor laser device (an oscillation wavelength of 300 nm to 3 nm depending on the composition of the active layer).
(It is possible to control up to 60 nm), which is very effective and can provide a highly reliable semiconductor laser device.

The substrate for a semiconductor device according to the present invention has a wide range of low-defect areas and is therefore highly reliable. Therefore, the light required in the fields of high-speed information / image processing and communication, measurement, medicine, and printing is required. -Applicable as a substrate for manufacturing electronic devices. Here, the semiconductor element or the opto-electronic device includes a field effect transistor, a semiconductor laser element, a semiconductor optical amplifier, a semiconductor light emitting element, a photodetector, and the like.

[Brief description of the drawings]

FIG. 1 is a view showing a manufacturing process of a semiconductor device substrate according to a first embodiment of the present invention;

FIG. 2 is a sectional view showing a semiconductor device substrate according to a second embodiment of the present invention;

FIG. 3 is a cross-sectional view illustrating a semiconductor device substrate according to a second embodiment of the present invention, in which a SiC substrate is removed from the semiconductor device substrate;

FIG. 4 is a sectional view showing a semiconductor laser device according to a third embodiment of the present invention;

FIG. 5 is a sectional view showing a semiconductor laser device according to a fourth embodiment of the present invention;

[Explanation of symbols]

11 SiC substrate 12 AlN buffer layer 13 GaN layer 14,17 SiO ₂ film 15,18 resist 16 Low defect GaN layer 19 GaN layer

Claims (11)

[Claims] A first step of crystal-growing a first group III nitrogen compound layer on a base substrate via a buffer layer made of AlN or GaN formed by a low-temperature growth method; A second step of patterning the group III nitrogen compound layer in a concavo-convex shape; a third step of heat-treating in a nitrogen and ammonia atmosphere to form a second group III nitrogen compound layer inside the concave portion; Group III nitrogen compound layer, the first Group III nitrogen compound layer and the buffer layer, leaving the first Group III nitrogen compound layer and the buffer layer below the second Group III nitrogen compound layer, the substrate A fourth step of removing the second group III nitrogen compound layer, the first group III nitrogen compound layer and the buffer layer as nuclei for crystal growth, and a third step until the surface is planarized. Fifth growth of group III nitrogen compound layer Method of manufacturing a substrate for a semiconductor device, which comprises a step. 2. After the fifth step, at least the second group III nitrogen compound layer is formed on the third group III nitrogen compound layer corresponding to the upper part of the second group III nitrogen compound layer. Forming a mask layer made of a material that cannot grow a group III nitrogen compound with a crystal, and forming a surface of the third group III nitrogen compound layer on which the mask layer is not formed with a nucleus for crystal growth of the group III nitrogen compound. 2. The method according to claim 1, wherein a sixth step of crystal-growing the group III nitrogen compound layer until the surface is flattened is performed. 3. After the sixth step, a space portion above the group III nitrogen compound layer formed in the immediately preceding step and between the mask layers formed immediately before the group III nitrogen compound layer is formed. A mask layer made of a material in which the group III nitrogen compound cannot grow crystals is formed thereon, and the mask layer is not formed.
3. The method according to claim 2, wherein the step of growing the group III nitrogen compound layer until the surface is flattened is performed at least once by using the surface of the group I nitrogen compound as a nucleus for crystal growth of the group III nitrogen compound. Method for manufacturing a substrate for a semiconductor element. 4. The method according to claim 1, wherein each of the group III nitrogen compound layers is formed while doping with a conductive impurity. 5. The method according to claim 1, wherein the base substrate is removed after the last of the steps. 6. The base substrate is made of sapphire, Si
C, ZnO, LiGaO2, LiAlO2, GaAs,
6. The method according to claim 1, wherein the substrate is any one selected from the group consisting of GaP, Ge, and Si. 7. The method according to claim 1, wherein the buffer layer and each of the group III nitrogen compound layers are formed by HVPE or MOCVD. 8. The group III nitrogen compound layer is composed of GaN, I
The method for manufacturing a substrate for a semiconductor device according to claim 1, wherein the method comprises one selected from the group consisting of nGaN, AlGaN, InAlGaN, InAlN, and InN. 9. A substrate for a semiconductor device manufactured by the method for manufacturing a substrate for a semiconductor device according to claim 1. 10. A semiconductor device comprising a semiconductor layer on a semiconductor device substrate manufactured by the method for manufacturing a semiconductor device substrate according to claim 1. Description: 11. A semiconductor element substrate provided on a semiconductor element substrate manufactured by the method for manufacturing a semiconductor element substrate according to any one of claims 1 to 8, wherein a semiconductor layer is provided. A semiconductor laser device, wherein a width of a stripe serving as an injection window is 1 μm or more.