JP2001111173A - Substrate for semiconductor device and method of fabrication thereof and semiconductor device using that substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fabricate a flat substrate for a semiconductor device in which defects are suppressed through a simple process. SOLUTION: A GaN buffer layer 12 and a GaN layer 13 are grown on a 6H-SiC substrate 11 and then removed up to the upper surface of the SiC substrate 11 by dry etching at a period of about 10 μm to form a line and space pattern. Subsequently, a GaN layer 16 is grown selectively and a 6H-SiC substrate 17 is brought into contact with the GaN layer 16 and secured thereto thus bonding a wafer. Subsequently, the 6H-SiC substrate 11 is removed by polishing or etching to expose the GaN layer 13 and the GaN layer 16. After removing the linear remaining GaN layer 13 and the GaN layer 16 up to the upper surface of the SiC substrate 17, a GaN layer 21 is grown selectively. Thereafter, an SiO2 film 22 is formed on the line part of the GaN layer 16 and a GaN layer 23 is grown selectively thereon. Finally, an SiO2 film 24 is formed on the SiO2 film 22 and a GaN layer 25 is grown selectively thereon.

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 more particularly, to a semiconductor device substrate made of a group III nitrogen compound and its manufacture. The present invention relates to a method and a semiconductor device and a semiconductor laser device using the semiconductor device 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 forming GaN on the sapphire substrate, using SiO ₂ as a mask,
After forming N, the n-GaN buffer layer, the n-InGaN crack prevention layer, the AlGaN / n-GaN modulation-doped superlattice cladding layer, the n-GaN optical waveguide layer, the undoped InGaN /
n-InGaN multiple quantum well active layer, p-AlGaN carrier block layer, p-GaN optical waveguide layer, AlGaN /
A structure in which a p-GaN modulation-doped superlattice cladding layer and a p-GaN contact layer are stacked has been reported. However, this semiconductor laser device still has a high defect density and has not been able to achieve high output reliability.

Also, Ext. Abstr. (MRS Fall Meet. Boston,
1998) G3.38, Pendeo-Ep by TSZheleva et al.
itaxy-A New Approach for Lateral Growth of Gallium
Nitride Structures is introduced. Here, S
After forming GaN without masking iO ₂ , the GaN is removed to the sapphire substrate in a stripe shape, and GaN is grown on the substrate. It is reported that a film is formed.

[0004] In addition, utilizing the above method, 1999
In SPIE Vol.3628.pp.158, it is reported that an InGaN multiple quantum well semiconductor laser device can be formed. However, the reliability is limited to a level of 5 mW, and the defect density needs to be reduced.

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, the short-wavelength semiconductor laser device has a problem in reliability and the like under a high output because the substrate has many crystal defects.

In view of the above circumstances, the present invention provides a semiconductor device substrate having high reliability and a low defect density even under high output oscillation, a method of manufacturing the same, a semiconductor device and a semiconductor laser using the semiconductor device substrate. It is intended to provide a device.

[0008]

According to a method of manufacturing a semiconductor device substrate of the present invention, a first group III substrate is formed on a first base substrate via a buffer layer made of AlN or GaN formed by a low-temperature growth method. The first step of forming a nitrogen compound layer, the crystal layer comprising the buffer layer and the first Group III nitrogen compound layer, up to the upper surface of the first base substrate in a stripe shape, or up to a part of the base substrate Remove it,
The crystal layer forms a line-and-space pattern consisting of a line portion left in a line shape and a space portion formed between the line portions, and a second Group III nitrogen compound layer thereon, A second step of forming the line portion as a growth nucleus of a crystal of a group III nitrogen compound until the line and space pattern disappears; and
A third step of bonding a second base substrate made of the same material as the first base substrate on the group I nitrogen compound layer, and reducing the thickness of at least the first base substrate from the back surface of the first base substrate. A fourth step of removing, with the second base substrate facing down, if the line portion is not removed by the fourth step, the second group III below the line portion and the line portion In the case where the line portion has been removed by the fourth step, the second group III nitrogen compound layer below the line portion is formed at least by the width of the line portion on the second base substrate. Until is exposed
Alternatively, a line and space formed by removing a part of the second base substrate and forming a line portion in which the second group III nitrogen compound layer is left in a line shape and a space portion formed between the line portions Is formed thereon, and a third group III nitrogen compound layer is formed thereon, and the line portion of the second group III nitrogen compound is used as a growth nucleus of a crystal of the group III nitrogen compound. And a fifth step of forming a line and space pattern of the nitrogen compound layer until the pattern disappears.

After the fifth step, a group III nitrogen compound is grown on at least the line width of the third group III nitrogen compound layer corresponding to the line portion of the second group III nitrogen compound. Forming a mask layer made of a material that cannot be
A sixth step of forming a group III nitrogen compound layer until the mask layer is covered with the surface of the group III nitrogen compound layer on which the mask layer is not formed as a growth nucleus of a crystal of the group III nitrogen compound is performed. You may. Further, after the sixth step, on the group III nitrogen compound layer formed in the immediately preceding step,
Forming a mask layer made of a material in which a group III nitrogen compound cannot grow crystals at least in a space corresponding to the space portion of the line-and-space pattern of the underlying mask layer; The step of forming a group III nitrogen compound layer until the mask layer is covered may be performed at least once using the surface of the group III nitrogen compound in which is not formed as a growth nucleus of a crystal of the group III nitrogen compound.

The above-mentioned group III nitrogen compound layer may be formed while doping impurities.

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

The base substrate is made of sapphire, SiC, Zn
O, LiGaO ₂ , LiAlO ₂ , GaAs, GaP, G
It is desirably any one selected from the group consisting of e and Si.

Further, the buffer layer and all the above III
The group III nitrogen compound layer by HVPE, MOCVD or M
It is desirable to form by BE method.

The group III nitrogen compound layer is formed of Ga
N, InGaN, AlGaN, InAlGaN, InA
Desirably, it is made of one selected from the group consisting of 1N and InN.

The substrate for a semiconductor element of the present invention is characterized by being manufactured by the method for manufacturing a substrate for a semiconductor element having the above structure.

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

Further, 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 above-described structure, and a current formed on the semiconductor layer. The width of a stripe serving as an injection window is 10 μm or more.

[0018]

According to the conventional method for manufacturing a substrate for a semiconductor device, a group III nitrogen compound is grown directly on a base substrate. However, since the lattice constant difference between the base substrate and the group III nitrogen compound is large, the group III nitrogen compound is grown. Penetration defects occurred in the compound layer. Then, the penetrating defect is partially formed in SiO 2
After suppressing with a mask such as a _two film, the group III nitrogen compound crystal was selectively grown, but since there is a penetrating defect in the group III nitrogen compound layer on the base substrate, from the place where the mask layer is not formed Penetration defects have grown, and there is a limit to reducing the defect density to a practical level. However, according to the method for manufacturing a semiconductor device substrate of the present invention, the first III
After growing the group III nitrogen compound layer, the buffer layer having a large number of defects and the first group III nitrogen compound layer are partially removed so as to form a line and space pattern, and a new group III nitrogen Since the compound crystal is selectively grown by utilizing the lateral growth of the crystal, a penetrating defect exists from the line portion to the upper portion of the line portion, but the group III between the newly crystallized line portion is present. The nitrogen compound layer has fewer defects.

A second base substrate made of the same material as the first base substrate is bonded thereon. Then, the first base substrate is removed, and after removing the buffer layer and the line part of the crystal layer composed of the first group III nitrogen compound layer and the second group III nitrogen compound layer below the line part, the third III By selectively growing the group-III nitrogen compound, defects are caused by interfacial defects existing on the bonding surface of the second base substrate and third defects left in a line.
Only defects slightly present in the group III nitrogen compound layer are present.

In the method of manufacturing a substrate for a semiconductor device according to the present invention, since the mask layer is formed above the line portion of the third group III nitrogen compound, it is possible to prevent defects from growing in the upper layer. Can be. Further, the third group III nitrogen compound between the mask layers is used as a nucleus for crystal growth, and
Selective growth of group III nitrogen compounds
A group III nitrogen compound layer can be obtained.

Further, a mask layer is further formed on the group III nitrogen compound layer formed in the previous step, at a position corresponding to the space portion of the lower mask layer, and at a position where the mask layer is not formed. By repeating the step of selectively growing a group III nitrogen compound using the exposed group III nitrogen compound layer as a crystal growth nucleus, defects can be reduced in each step, and ultimately completely free of defects A substrate can be obtained.

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

Further, by removing the base substrate after the crystal growth of the group III nitrogen compound, electric conduction can be obtained from the back surface of the substrate.

According to the semiconductor device of the present invention, since the semiconductor device is formed on a substrate having no defect, the reliability can be improved. Further, when a semiconductor element is formed on a substrate from which the base substrate has been removed, an electrode can be formed on the back surface.

[0025]

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

A method for manufacturing a semiconductor device substrate according to the first embodiment of the present invention will be described. FIG. 1 shows a manufacturing process of the semiconductor device substrate.

As shown in FIG. 1a, trimethylgallium (TMG) and ammonia are used as growth materials, silane gas is used as an n-type dopant gas, and cyclopentadienylmagnesium is used as a p-type dopant. (0001) plane 6 using (Cp ₂ Mg)
An AlN buffer layer 12 is formed on an H-SiC substrate 11 at a temperature of 500 ° C. with a thickness of about 20 nm. Subsequently, the temperature is set to 1050 ° C., and the GaN layer 13 is grown to about 2 μm.
After that, an SiO ₂ layer 14 is formed, a resist 15 is applied, and then, using normal lithography,

[0028]

(Equation 1)

The 5 μm wide SiO ₂ film 14 is removed in the direction,
A line and space pattern is formed at a period of about 10 μm so that the width of the remaining line portion becomes 5 μm.

Next, as shown in FIG. 1B, using the resist 15 and the SiO ₂ film 14 as a mask, the buffer layer 12 and the GaN layer 13 are dry-etched using a chlorine-based gas.
It is removed up to the upper surface of the C substrate 11. At this time, the SiC substrate 11 may be etched. Next, resist 15 and SiO ₂
After removing the film 14, the GaN layer 16 is selectively grown to about 20 μm. At this time, the space portion is finally filled by the lateral growth, and the surface is flattened. At this point, the Si
Since the lattice constant difference between the C substrate 11 and AlN is large, threading dislocations are generated in the upper part of the line portion of the layer composed of the buffer layer 12 and the GaN layer 13. Here, a large lattice constant difference means that
Assuming that the lattice constant of the SiC substrate is as and the lattice constant of GaN is ag, the value represented by (ag-as) / as is ± 0.0
Indicates that it is greater than 05.

Next, as shown in FIG. 1C, a 6H-SiC substrate 17 having a mirror-polished surface is fixed in contact with the GaN layer 16 and the temperature is increased to about 800 to 1100 ° C. The wafer is bonded in a hydrogen atmosphere. At this time, the interface 18 has an interface defect.

Next, as shown in FIG. 1D, 6H-SiC
The substrate 11 and the AlN buffer layer 12 are removed by polishing or etching to expose the GaN layer 13 and the GaN layer 16.

Next, as shown in FIG. 1e, SiO ₂ film 19
Is formed, a resist 20 is applied, and Si over the GaN layer 13 is formed.
Patterning is performed so that the O ₂ film 19 disappears.

Next, as shown in FIG.
The GaN layer 13 and the GaN layer 16 left in the form of a line having a high dislocation density adhered to the substrate 11 are dry-etched using a chlorine-based gas.

[0035]

(Equation 1)

After removing the resist 20 to the upper surface of the SiC substrate 17 in the direction, the resist 20 and the SiO ₂ film 19 are removed.

Next, as shown in FIG. 1g, a GaN layer 21 is selectively grown to a thickness of about 20 μm. At this time, the space portion is finally filled by the lateral growth, and the surface is flattened.

Next, as shown in FIG. 1h, SiO ₂ film 22
Is formed, and the SiO ₂ film 22 located at the center of the space between the lines formed by leaving the GaN layer 16 is removed by about 3 μm. Further, the growth temperature is set to 1050 ° C.
The N layer 23 is selectively grown to about 20 μm. At this time, the space is finally filled by the lateral growth, and the surface is flattened.

[0039] Subsequently, as shown in FIG. 1i, SiO ₂
A film 24 is formed, and the SiO ₂ film 24 located at the center of the line portion formed by leaving the SiO ₂ film 22 is removed by about 3 μm in width. On top of that, the GaN layer was grown at a growth temperature of 1050 ° C.
Selectively grow 25. At this time, the space portion is filled by the lateral growth, the surface is flattened, and the GaN substrate is completed.

In this embodiment, after the GaN layer 13 and the GaN layer 16 are exposed, the operations shown in FIGS. 1E and 1F are performed.
When the N layer 16 is exposed, the removal operation by polishing or the like may be stopped, and the operation shown in FIGS. 1E and 1F may be performed. After performing operations such as polishing until the GaN layer 13 is completely removed, the operations shown in FIGS. 1E and 1F may be performed.

On the GaN substrate thus manufactured, GaN
A semiconductor light emitting device and an electronic device can be manufactured by crystal-growing a system semiconductor layer, for example, GaN, InGaN, AlGaN, InGaAlN, or the like.

On the GaN substrate manufactured above, Ga was added.
After growing the N layer by about 100 to 200 μm, the SiC substrate as the base substrate is removed, and then a GaN-based semiconductor layer such as GaN, InGaN, AlGaN and InGaN is removed.
By growing crystals of GaAlN or the like, a semiconductor light emitting element and an electronic device can be manufactured.

The base substrate is a (0001) plane 4H-Si
A C substrate may be used.

In the present embodiment, the case of undoping without doping impurities when the GaN layer is selectively grown has been described.
Type GaN conductive substrate can be manufactured. When Mg is doped as a p-type impurity, either a heat treatment is performed in a nitrogen atmosphere after growth or a growth is performed in a nitrogen-rich atmosphere to activate Mg. You may.

As a method of growing GaN, Ga which is a reaction product of gallium (Ga) and hydrogen chloride (HCl) is used.
Hydride VP using Cl and ammonia (NH ₃ )
The E method may be used.

In this embodiment, Si is used as a base substrate.
The case where the C substrate is used has been described, but ZnO, Li
GaO ₂ , LiAlO ₂ , GaAs, GaP, Ge, Si
May be used for the base substrate.

In this embodiment, the case where SiO ₂ is used as the mask material has been described.
A mask material such as N, AlN, or TiN having good heat resistance against high temperatures may be used.

A semiconductor laser device according to a second embodiment of the present invention will be described, and a cross-sectional view thereof is shown in FIG.

In the same manner as in the first embodiment, the GaN layer 25 is manufactured by using the substrate manufacturing method by wafer bonding. The same reference numerals are given to each element, and the description is omitted.

As shown in FIG. 2, an n-
GaN buffer layer 26, 150 pairs of n-Al _0.14 Ga
_{The 0.86} N (2.5 nm) / GaN (2.5 nm) superlattice cladding layer 27 is formed of an n-GaN optical waveguide layer 28 and n-In _0.02 G
a _0.98 N (10.5 nm) / n-In _0.15 Ga _0.85 N
(3.5 nm) triple quantum well active layer 29, p-Al _0.2 G
a _{0 .8} N carrier block layer 30, p-GaN optical waveguide layer 3
1,150 pairs of p-Al _0.14 Ga _0.86 N (2.5 n
m) / GaN (2.5 nm) superlattice cladding layer 32, p-
The GaN contact layer 33 is laminated.

Here, Mg is used as the p-type impurity. As a method of activating Mg, either a method of performing heat treatment in a nitrogen atmosphere after crystal growth or a method of performing growth in a nitrogen-rich atmosphere may be used.

Subsequently, an SiO ₂ film 34 (not shown) is formed, and the SiO ₂ film 34 outside the stripe region having a width of 2 μm is removed by ordinary lithography. By selective etching with RIE (Reactive Ion Etching Equipment)
Etching is performed partway through the p-type superlattice cladding layer 32.
The remaining thickness of the cladding layer in this etching is a thickness that can achieve the fundamental transverse mode oscillation. Next, the SiO ₂ film 34 is removed, a SiO ₂ film 35 is subsequently formed, the SiO ₂ film 35 on the stripe serving as a current injection window is removed, and a p-electrode 36 made of Ni / Au is formed. Thereafter, the substrate is polished and Ti /
An n electrode 37 made of Au is formed. A high-reflection coat and a low-reflection coat are applied to the cavity surface formed by cleaving the sample, and thereafter, a chip is formed to complete a semiconductor laser device.

The wavelength band λ at which the semiconductor laser device oscillates
As for the active layer, In _x4 Ga _1-x4 N is used as an active layer, and the composition is set to 0.
By setting ≦ X4 ≦ 0.5, 360 ≦ λ ≦ 550 (n
Control up to the range of m) is possible.

The semiconductor layer may be formed by inverting the conductivity, that is, by switching the n-type and the p-type.

In the present embodiment, the semiconductor laser device that oscillates in a fundamental mode with a narrow stripe has been described. However, the present invention can be applied to the manufacture of a semiconductor laser device having a wide stripe of 10 μm or more.

Next, a description will be given of a semiconductor laser device according to a third embodiment of the present invention. FIG. 3 is a sectional view of the semiconductor laser device.

First, a method for manufacturing the GaN substrate 41 will be described. With reference to FIG. 1, the GaN layer 25 is manufactured by the method of manufacturing a semiconductor device substrate according to the first embodiment. Next, a GaN substrate 41 is formed by peeling off the rear surface of the substrate 17 to the middle of the GaN layer 25 and removing it. Next, as shown in FIG. 3, an n-GaN buffer layer 42 and 150 pairs of n-Al _0.14 Ga _0.86 N
The (2.5 nm) / GaN (2.5 nm) superlattice cladding layer 43 is formed of an n-GaN optical waveguide layer 44 and n-In _0.02 Ga _0.98
N (10.5 nm) / n-In _0.15 Ga _0.85 N (3.5
nm) triple quantum well active layer 45, p-Al _0.2 Ga _0.8 N carrier blocking layer 46, p-GaN optical waveguide layer 47, 150 pairs of p-Al _0.14 Ga _0.86 N (2.5 nm) / GaN
(2.5 nm) A superlattice cladding layer 48 and a p-GaN contact layer 49 are laminated. Here, Mg is used as the p-type impurity. As a method for activating Mg, either a method of performing a heat treatment in a nitrogen atmosphere after crystal growth or a method of performing growth in a nitrogen-rich atmosphere may be used. Subsequently, an SiO ₂ film 50 (not shown) is formed, and the 2 μm SiO ₂ film 50 outside the stripe region serving as a current injection window is removed by ordinary lithography. Etching is performed halfway in the p-type superlattice cladding layer 48 by selective etching using RIE (reactive ion etching apparatus). The remaining thickness of the cladding layer in this etching is a thickness that can achieve the fundamental transverse mode oscillation. Thereafter, the SiO ₂ film 50 is removed, a SiO ₂ film 51 is subsequently formed, the SiO ₂ film 51 on the stripe serving as a current injection window is removed, and a Ni / Au p
An electrode 52 is formed. Thereafter, the substrate is polished and Ti / Au
An n-electrode 53 is formed. A high-reflection coat and a low-reflection coat are applied to the cavity surface formed by cleaving the sample, and thereafter, a chip is formed to complete a semiconductor laser device.

The wavelength band λ at which the semiconductor laser device oscillates
As for the active layer, In _x4 Ga _1-x4 N is used as an active layer, and the composition is set to 0.
By setting ≦ X4 ≦ 0.5, 360 ≦ λ ≦ 550 (n
Control up to the range of m) is possible.

The semiconductor layer is inverted in conductivity (n-type and p-type).
(Replace the mold).

As shown in this embodiment, by removing the base substrate, Ga
An electrode can be formed on the back surface of the N substrate 41.

Further, in this embodiment, the semiconductor laser element that oscillates in a fundamental mode with a narrow stripe has been described. However, the present invention can be applied to the manufacture of a semiconductor laser device having a wide stripe of 10 μm or more.

Next, a method of manufacturing a semiconductor device substrate according to a fourth embodiment of the present invention will be described. FIG. 4 shows a process of manufacturing the semiconductor device substrate.

As shown in FIG. 4A, trimethylgallium (TMG) and ammonia were used as growth materials, silane gas was used as an n-type dopant gas, and cyclopentadienyl magnesium was used as a p-type dopant by metal organic chemical vapor deposition. (0001) plane 6 using (Cp ₂ Mg)
An AlN buffer layer 62 is formed on an H-SiC substrate 61 at a temperature of 500 ° C. with a thickness of about 20 nm. Subsequently, the temperature is set to 1050 ° C., and the GaN layer 63 is grown to about 2 μm.
After forming a SiO ₂ layer 64 thereon and applying a resist 65, using normal lithography,

[0064]

(Equation 1)

A line-and-space pattern is formed at a period of about 10 μm in the stripe region from which the SiO ₂ film 64 having a width of 3 μm has been removed in the direction.

Next, as shown in FIG. 4B, using the resist 65 and the SiO ₂ film 64 as a mask, the buffer layer 62 and the GaN layer 63 are dry-etched using a chlorine-based gas.
It is removed up to the upper surface of the C substrate 61. At this time, the SiC substrate 11 may be etched. After removing the resist 65 and the SiO ₂ film 64, a GaN layer 66 is selectively grown to about 20 μm. At this time, the space portion is finally filled by the lateral growth, and the surface is flattened. At this point, since the lattice constant difference between the SiC substrate and AlN is large, the buffer layer 62 and GaN
Threading dislocations have occurred in the upper portion of the line portion of the layer composed of the N substrate 63.

Next, as shown in FIG. 4C, a 6H-SiC substrate 67 having a mirror-polished surface is brought into contact with and fixed to the GaN layer 66, and the temperature is raised to about 800 to 1100 ° C. Alternatively, the wafer is bonded in a hydrogen atmosphere.
An interface defect exists on the bonding surface 68 between the GaN layer 66 and the 6H-SiC substrate 67.

Next, as shown in FIG. 4D, 6H-SiC
The substrate 61 and the AlN buffer layer 62 are removed by polishing or etching to expose the GaN layer 63 and the GaN layer 66.

Next, as shown in FIG. 4e, SiO ₂ film 69
Is formed, a resist 70 is applied, and Si over the GaN layer 63 is formed.
Patterning is performed so that the O ₂ film 69 disappears.

Next, as shown in FIG. 4F, 6H-SiC
The GaN layer 63 and the GaN layer 66, which have a high dislocation density adhered to the substrate 67 and are left in a line, are dry-etched using a chlorine-based gas.

[0071]

(Equation 1)

In the direction, the upper surface of the SiC substrate 67 is removed,
The resist 70 and the SiO ₂ film 69 are removed.

Next, as shown in FIG. 4G, a GaN layer 71 is selectively grown to about 20 μm. At this time, the space portion is finally filled by the lateral growth, and the surface is flattened.

Next, as shown in FIG. 4H, the GaN layer 71 and the GaN layer 66 are removed in a V-groove shape up to the upper surface of the SiC substrate 67 by wet etching.

Thereafter, as shown in FIG.
Is selectively grown to about 20 μm. At this time, the lateral growth eventually fills the space portion, the V-groove is buried, and the surface is flattened. As a result, a GaN substrate having a low dislocation density over the entire surface of the substrate can be obtained.

In this embodiment, after the GaN layer 63 and the GaN layer 66 are exposed, the operations shown in FIGS. 4E and 4F are performed.
When the N layer 66 is exposed, the removal operation by polishing or the like may be stopped, and the operation shown in FIGS. 4E and 4F may be performed. Further, after performing operations such as polishing until the GaN layer 63 is completely removed, the operations shown in FIGS. 4E and 4F may be performed.

The shape by wet etching is as follows:
The shape is not limited to the V-groove shape and may be an inverted trapezoid shape.

In the first embodiment, a mask layer is provided on the GaN layer 21 in order to prevent the occurrence of a penetrating defect. However, as in the present embodiment, the defect remaining in a line is removed. The existing GaN layer 66 may be removed in the form of a V-groove, and a GaN layer 72 may be selectively grown thereon, thereby finally obtaining a defect-free GaN substrate.

In the first and fourth embodiments, GaN was grown as a group III nitrogen compound.
AlGaN, InGaN, InAlGa instead of aN
N, InAlN or InN may be grown.

[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 laser device according to a second embodiment of the present invention;

FIG. 3 is a sectional view showing a semiconductor laser device according to a third embodiment of the present invention;

FIG. 4 is a view showing a process of manufacturing a semiconductor device substrate according to a fourth embodiment of the present invention;

[Explanation of symbols]

11,17,61,67 SiC substrate 12,62 AlN buffer layer 13,63 GaN layer 14,19,22,24,64,69 SiO ₂ film 15,20,65,70 Resist 16,21,23,25, 66,71,72 GaN layer 26,42 GaN buffer layer 27,43 AlGaN / GaN superlattice cladding layer 28,44 GaN optical waveguide layer 29,45 InGaN / InGaN triple quantum well active layer 30,46 AlGaN carrier block layer 31, 47 GaN optical waveguide layer 32,48 AlGaN super lattice cladding layer 33,49 GaN contact layer 35,51 SiO ₂ film 36,52 p electrode 37,53 n electrode

Claims (11)

[Claims] A first step of forming a first group III nitrogen compound layer on a first base substrate via an AlN or GaN buffer layer formed by a low-temperature growth method; A line formed by removing the crystal layer made of the first group III nitrogen compound layer in a stripe form up to the upper surface of the first base substrate or up to a part of the base substrate, leaving the crystal layer in a line shape. And a space portion formed between the line portions, a line-and-space pattern is formed, and a second group III nitrogen compound layer is formed thereon, and the line portion is formed by growing a group III nitrogen compound crystal. A second step of forming a nucleus until the line and space pattern disappears, and contacting a second base substrate made of the same material as the first base substrate on the second group III nitrogen compound layer. A fourth step of removing at least the thickness of the first base substrate from the back surface of the first base substrate; and If not removed by the step, the line part and the second group III nitrogen compound layer below the line part, if the line part is removed by the fourth step, the line part Removing the second group III nitrogen compound layer below at least the width of the line portion until the second base substrate is exposed or a part of the second base substrate to remove the second group III nitrogen compound layer. Form a line and space pattern consisting of a line portion where the nitrogen compound layer is left in a line shape and a space portion formed between the line portions, and further form a third group III nitrogen compound layer thereon. The second group III nitrogenation A fifth step of forming a line portion of the compound as a growth nucleus of a group III nitrogen compound crystal until the line and space pattern of the second group III nitrogen compound layer disappears. A method for manufacturing an element substrate. 2. After the fifth step, a group III nitrogen compound is grown on at least the line width of the third group III nitrogen compound layer corresponding to the line portion of the second group III nitrogen compound. A mask layer made of a material that cannot be formed is formed.
2. The method according to claim 1, further comprising a sixth step of forming a group III nitrogen compound layer as a growth nucleus of a group II nitrogen compound crystal until the mask layer is covered. Method. 3. After the sixth step, a portion corresponding to the space portion of the line and space pattern of the underlying mask layer on the group III nitrogen compound layer formed in the immediately preceding step, At least in the width of the space, III
Forming a mask layer made of a material in which the group III nitrogen compound cannot grow crystals, and using the surface of the group III nitrogen compound on which the mask layer is not formed as a growth nucleus for the crystal of the group III nitrogen compound;
The step of forming a group II nitrogen compound layer until the mask layer is covered is performed at least once.
A method for manufacturing a substrate for a semiconductor element as described in the above. 4. The method according to claim 1, wherein the group III nitrogen compound layer is formed while doping impurities.
4. The method for manufacturing a semiconductor element substrate according to 2 or 3. 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, LiGaO ₂ , LiAlO ₂ , GaAs, G
6. The method according to claim 1, wherein the substrate is any one selected from the group consisting of aP, Ge, and Si. 7. The buffer layer and all of the III
Group III compound layer by HVPE, MOCVD or M
7. The method according to claim 1, wherein the electrode is formed by a BE method.
A method for manufacturing a substrate for a semiconductor element according to any one of the preceding claims. 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 formed by the method for manufacturing a semiconductor element substrate according to claim 1, further comprising a semiconductor layer, and formed on the semiconductor layer. The width of the stripe serving as the current injection window is 10μ.
m or more.