JP3139445B2 - GaN-based semiconductor growth method and GaN-based semiconductor film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for epitaxially growing a semiconductor crystal, and more particularly to a method for epitaxially growing a group III-V compound semiconductor crystal film on a substrate having a different lattice constant and a different coefficient of thermal expansion. The present invention relates to a group III-V compound semiconductor film. In particular, it is effective in applying a method of epitaxially growing a GaN-based semiconductor in which formation of a semiconductor film with few crystal defects is difficult.

[0002] Further, the present invention relates to a GaN-based semiconductor device and a method of manufacturing the same, and more particularly, to a GaN-based semiconductor device formed on a GaN semiconductor film having few crystal defects and a method of manufacturing the same.

[0003]

2. Description of the Related Art Gallium nitride (GaN), which is a group III-V compound semiconductor, has attracted attention as a blue light emitting device material because it has a large bandgap of 3.4 eV and is a direct transition type.

[0004] As a substrate material for manufacturing a light emitting device using this material, it is desirable to use a bulk crystal of the same substance as the epitaxial layer to be grown. However, in a crystal such as GaN, it is very difficult to produce a bulk crystal due to a high dissociation pressure of nitrogen.
Therefore, when fabricating a device using a material for which fabrication of a bulk crystal is extremely difficult, for example, sapphire (Al
Substrates having completely different physical properties such as lattice constant and thermal expansion coefficient and chemical properties such as ₂ O ₃ ) substrates have been used.

[0005]

When epitaxial growth is performed on such a hetero-substrate, strain and defects are generated in the substrate and the epitaxial layer, and cracks are generated particularly when a thick film is grown. "Japanese Journal of Applied Physics, Vol. 32 (1993), pp. 1528-1533"
(Jpn.J. Appl.Phys.Vol 32 (1993) pp.1528-153
3). In such a case, not only the performance of the device becomes extremely poor, but also the result that the grown layer is broken into pieces is often caused.

In order to obtain a high-quality epitaxially grown layer having a low dislocation density in the lattice-mismatched epitaxial growth, a 1 μm SiO ₂ film is firstly grown.
Japanese Patent Application Laid-Open No. 8-64791 discloses that a GaN film is selectively grown on a sapphire substrate on which a stripe is formed by a film to concentrate lattice defects and dislocations in a specific region. However, in the example of JP-A-8-64791, Si
Since growth did not occur in the O ₂ film portion, a flat growth layer could not be obtained on the entire surface, and restrictions were placed on element formation locations.

[0007] An object of the present invention is to provide a method for producing a thin film even when epitaxial growth is performed using a heterosubstrate having a different lattice constant or thermal expansion coefficient. An object of the present invention is to provide a growth method for obtaining an epitaxial growth layer in which cracks are less likely to occur.

Another object of the present invention is to provide a GaN-based semiconductor film having few crystal defects by utilizing the above-mentioned epitaxial growth for growing a GaN-based semiconductor.

Another object of the present invention is to provide a GaN-based semiconductor film formed by the above-mentioned epitaxial growth.
GaN-based semiconductor device (for example, GaN-based semiconductor light-emitting device) that can obtain excellent device characteristics by producing a GaN-based semiconductor device structure (for example, GaN-based semiconductor light-emitting device structure)
Is to provide.

[0010]

According to the present invention, there is provided a method for growing a GaN-based semiconductor, comprising the steps of: forming a growth region on a substrate surface using a patterned mask material; And growing while forming a facet structure of a GaN-based semiconductor having a different lattice constant and coefficient of thermal expansion, and covering the mask material together with the facet structure of the GaN-based semiconductor in an adjacent growth region to planarize the surface. It is characterized. Further, each of the above steps is repeated on the flattened surface.

Further, according to the method of growing a GaN-based semiconductor of the present invention, the GaN-based semiconductor having the same material as the GaN-based semiconductor grown in the growth region or having a similar lattice constant or thermal expansion coefficient is formed on the substrate surface. After forming the semiconductor, a growth region formed by the patterned mask material is formed.

Further, the growth region formed by using the mask material has a stripe shape, a rectangular shape, a round shape, or a triangular shape. Further, the substrate is made of MgAl ₂
O ₄ substrate, Si substrate, ZnO substrate, SiC substrate, LiG
aO ₂ substrate or Al ₂ O ₃ substrate, wherein the GaN-based semiconductor is GaN, InGaN, Al
It is characterized by being selected from any one of GaN.

Further, the GaN-based semiconductor is GaN,
Selected from one of InGaN and AlGaN,
Further, the mask has a stripe shape, and a side wall of the facet structure is a {1-101} plane. Alternatively, the GaN-based semiconductor is Ga
N, InGaN, or AlGaN, and the mask has a stripe shape, and the stripe direction is a <11-20> direction or a <1--20> direction.
100> direction.

After the formation of the GaN-based semiconductor,
removing at least the substrate and the mask material from the aN-based semiconductor.

The method of growing a GaN-based semiconductor according to the present invention is characterized in that the method further includes a step of growing a device structure after the formation of the GaN-based semiconductor. Further, the device structure is one of a laser, an FET, and an HBT.

The GaN-based semiconductor film of the present invention comprises a substrate having a different lattice constant or thermal expansion coefficient from a GaN-based semiconductor, a patterned mask material for forming a growth region on the substrate surface, and a facet structure formed by the growth region. A GaN-based semiconductor that grows while being formed and covers the mask material together with the growth of the GaN-based semiconductor in the adjacent growth region, and that the facet structure is embedded and formed by the growth of the GaN-based semiconductor. It is characterized by.

Furthermore, at least the substrate and the mask material are removed from the GaN-based semiconductor film.

In addition, a GaN-based semiconductor having the same material as the GaN-based semiconductor grown in the growth region or a GaN-based semiconductor having similar properties such as a lattice constant and a thermal expansion coefficient is formed on the surface of the substrate. In which a growth region made of a mask material is formed.

Furthermore, the present invention is characterized in that the growth region formed using the mask material has a stripe shape, a rectangular shape, a round shape, or a triangular shape. The substrate is a MgAl ₂ O ₄ substrate, Si substrate, ZnO substrate, SiC substrate, LiGaO ₂
Substrate or an Al ₂ O ₃ substrate.
The N-based semiconductor is characterized by being selected from any one of GaN, InGaN, and AlGaN.

Further, GaN-based semiconductors include GaN, In
The mask is selected from one of GaN and AlGaN, and the shape of the mask is a stripe shape, and a side wall of the facet structure is a {1-101} plane. Alternatively, GaN-based semiconductors include GaN, I
The mask is selected from one of nGaN and AlGaN, and the shape of the mask is a stripe shape, and the stripe direction is a <11-20> direction or a <1-100> direction.
Direction.

The GaN-based semiconductor device of the present invention is characterized in that
A device structure is formed on the aN-based semiconductor film. Further, the device structure is laser, FE
T or HBT.

[0022]

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

(First Embodiment) A first embodiment of the present invention will be described with reference to FIG. 1 taking as an example the epitaxial growth of a group III-V compound semiconductor.

First, a group III-V compound semiconductor 12 having a property different from that of the substrate material and having the same property as the material to be grown in the next step or having a property similar to the material in the lattice constant and the coefficient of thermal expansion. Is grown on a substrate, and a mask 14 for limiting a growth region on the substrate is formed on the surface by using photolithography and wet etching. The shape of the mask is a stripe. At this time, the thickness of the mask 14 is about 10 nm to 2 μm, and the stripe width of the growth region 13 and the mask 14 is usually 0.1 μm to 10 μm.
It was about μm. (FIG. 1 (a)).

Next, a group III-V compound semiconductor film is epitaxially grown on the growth region. The substrate with the mask 14 is inserted into a reaction tube of an epitaxial apparatus, and hydrogen gas, nitrogen gas, or a mixed gas of hydrogen and nitrogen and V
The substrate 11 is heated to a predetermined growth temperature while supplying a group source gas. After the temperature is stabilized, a group III raw material is supplied to grow the group III-V compound semiconductor 15 in the growth region 13. The crystal growth method is preferably a vapor phase growth (VPE: Va) by a chloride transport method using a chloride as a group III raw material.
por Phase Epitaxy), but metalorganic compound vapor phase growth (MOCVD:
Metal Organic Vapor Phase Epitaxy) may be used.

The III-V compound semiconductor 15 does not grow on the mask 14 in the initial stage, and crystal growth occurs only in the growth region 13, and a facet structure is formed in the III-V compound semiconductor 15 on the growth region. Is done. I at this time
The growth conditions for the II-V compound semiconductor 15 are as follows: a growth temperature of 650 ° C. to 1100 ° C. so that a facet structure is formed;
The operation is performed within the range of the supply amount of the group V raw material that supplies double the amount. (Figure 1
(B)).

When epitaxial growth is further continued, I
Since the group II-V compound semiconductor 15 grows in a direction perpendicular to the facet structure, it covers not only the growth region but also the mask 14. Then, it comes into contact with the facet structure of the group III-V compound semiconductor 15 in the adjacent growth region (FIG. 1C).

When the epitaxial growth is further continued, the facet structure is buried (FIG. 1D), and finally, the III-V compound semiconductor film 1 having a flat surface is formed.
5 can be obtained (FIG. 1 (e)).

Normally, when a group III-V compound semiconductor having a different lattice constant and a different coefficient of thermal expansion is grown on a substrate, dislocations due to crystal defects generated at the interface with the substrate extend in a direction perpendicular to the interface. In addition, even if the thickness of the epitaxial film is increased, no reduction in dislocation is observed.

In the method according to the present embodiment, a facet structure is formed in a growth region by selective growth. This facet appears because the growth rate is slower than other aspects. With the appearance of the facet, the dislocation proceeds toward the facet, and the dislocation extending perpendicular to the substrate cannot be extended in the vertical direction. It was found that the crystal defects were bent laterally with the growth of the facet, and as the thickness of the epitaxial film increased, the crystal defects decreased in the growth region and appeared at the edge of the crystal or formed a closed loop. .
As a result, defects in the epitaxial film can be reduced. By forming and growing the facet structure in this manner, crystal defects can be significantly reduced.

In particular, in the vapor phase growth by the chloride transport method using chloride as a group III raw material, the growth of the group III-V compound semiconductor 15 is rapid, so that the same facet structure as the substrate surface in the facet structure disappears quickly. Therefore, the dislocations extending perpendicular to the substrate will soon extend in a direction different from the substrate surface in the facet structure, and the dislocations extending vertically in the group III-V compound semiconductor 15 can be greatly reduced.

The organic metal compound vapor phase growth using an organic metal as the group III raw material has a lower growth rate than the vapor phase growth by the chloride transport method.
What is necessary is just to make the face which is the same as the substrate face in the facet structure of the group V compound semiconductor 15 disappear quickly. For example, if the area of the mask with respect to the growth region is increased, the supply amount of the growth species from above the mask is increased.
The growth of the group V compound semiconductor 15 can be stopped.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIG. 5 taking the example of epitaxial growth of a group III-V compound semiconductor.

FIGS. 5A to 5B are manufactured by the same steps as those of FIGS. 1A to 1E of the first embodiment, and the description is omitted. In the second embodiment, III-
After epitaxially growing a group V compound semiconductor and flattening the growth layer, a second mask is provided (FIG. 5C).
A facet structure is formed and flattened as in the first embodiment (FIG. 5D).

In the second embodiment, III is formed by repeating the manufacturing steps shown in FIGS.
The defect density of the group-V compound semiconductor film can be further reduced.

The first embodiment or the second embodiment is effective for crystal growth of a material having a different lattice constant or thermal expansion coefficient from that of the substrate, such as Al ₂ O ₃ , Si, SiC,
G to a substrate of MgAl ₂ O ₄ , LiGaO ₂ , ZnO, etc.
III-V such as aN, GaAlN, InGaN, InN
It can be applied to the growth of group III compound semiconductors.

In FIG. 1 or FIG. 5, a mask is formed on the surface of a group III-V compound semiconductor film having the same property as the substance grown on the substrate in the next step, or having a property similar to the substance in lattice constant or thermal expansion coefficient. Although the example of the formation is shown, the substrate 1
Similar effects can be obtained by directly forming a mask on one surface and performing the processes of FIGS. 1B to 5E or FIGS. 5B to 5D.

Further, in the present embodiment, the growth region using the stripe pattern as the mask 14 has been described. However, the present invention is not limited to this. Rectangular,
A round or triangular mask may be used.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
An embodiment will be described. In the third embodiment,
The epitaxial growth of the group III-V compound semiconductor described in the first embodiment or the second embodiment is performed by Ga.
A GaN-based semiconductor film is formed for use in growing an N-based semiconductor.

In the third embodiment, the epitaxial growth described in the first embodiment or the second embodiment is applied to a GaN-based semiconductor, and the description of common parts will be simplified.

First, a mask for limiting a growth region on a substrate is formed on a substrate material having a different thermal expansion coefficient or lattice constant from that of a GaN-based semiconductor by using photolithography and wet etching.

Next, the GaN-based semiconductor is epitaxially grown in the growth region. A crystal growth method for a GaN-based semiconductor grown in a growth region employs gallium (G
a) Vapor phase growth (VPE: Vapo) by chloride transport method using gallium chloride (GaCl) which is a reaction product of hydrogen chloride (HCl) and ammonia (NH ₃ ) gas as a group V raw material.
r Phase Epitaxy), hydride VPE method, MOCVD (Metal Organic Vapor Phase Epitaxy)
Use y). The growth temperature is from 650 ° C. to 1100 ° C., and the supply amount of the group V raw material may be 1 to 200,000 times the supply amount of the group III raw material.

In the epitaxial growth of the GaN-based semiconductor layer, as in the first embodiment, the GaN-based semiconductor does not grow on the mask in the initial stage, and crystal growth occurs only in the growth region. A facet structure having a plane orientation different from the plane orientation of the substrate is formed on the film.

When the epitaxial growth is continued, the GaN-based semiconductor grows in a direction perpendicular to the facet structure, so that it covers not only the growth region but also the mask. Then, it comes into contact with the facet structure of the GaN-based semiconductor in the adjacent growth region. When the epitaxial growth is further continued, the facet structure is buried with the GaN-based semiconductor, and finally, a GaN-based semiconductor film having a flat surface can be obtained.

GaN is difficult to fabricate in bulk crystals,
In conventional crystal growth of GaN-based semiconductors, sapphire substrates, SiC substrates, and the like have been used as substrates, but these substrates have different lattice constants and thermal expansion coefficients from GaN-based semiconductors. For this reason, when epitaxial growth of a GaN-based semiconductor is performed, dislocations due to crystal defects generated at the interface with the substrate extend in the direction perpendicular to the interface, and even if the epitaxial film is thickened, no reduction in the dislocation was observed.

In the epitaxial growth method according to the present embodiment, a growth region selectively formed by a mask material on a substrate material having a different thermal expansion coefficient or lattice constant from a GaN-based semiconductor has a plane orientation different from the substrate plane orientation. A GaN-based semiconductor having a facet structure is epitaxially grown. This facet appears because the growth rate is slower than other planes, and the appearance of the facet causes dislocations generated near the interface between the substrate and the GaN-based semiconductor to proceed toward the facet, and dislocations extending perpendicular to the substrate. Cannot extend in the vertical direction.

Therefore, the crystal defects of the GaN-based semiconductor are bent laterally with the growth of the facet, and as the film thickness increases by epitaxial growth of the GaN-based semiconductor, the crystal defects decrease in the growth region and emerge at the edge of the crystal. Or form a closed loop. As a result, defects in the epitaxial film can be reduced.

As described above, by growing a GaN-based semiconductor film having a facet structure in a growth region selectively formed by a mask on a substrate, crystal defects of the GaN-based semiconductor film can be significantly reduced. .

Further, the Ga obtained in the third embodiment is
The N-based semiconductor film is used as a substrate of a GaN-based semiconductor film having few crystal defects by removing a substrate (a sapphire substrate or the like), a mask, and part of the GaN-based semiconductor after growing the film to a desired thickness. be able to. By manufacturing a GaN-based semiconductor element on such a GaN-based semiconductor film, G
The crystallinity of the stacked structure of the aN-based semiconductor element can be improved.

When the GaN-based semiconductor device is a GaN-based semiconductor light-emitting device, an electrode can be formed on the back surface of the GaN-based semiconductor light-emitting device, which has been a problem with a sapphire substrate or the like.

Further, when the GaN-based semiconductor light emitting device is a GaN-based semiconductor laser, even if a laser structure is formed on a heterosubstrate having a cleavage plane different from that of the GaN-based semiconductor, a cavity mirror can be manufactured by cleavage.

Although the formation of the GaN-based semiconductor film in the third embodiment has been described using the epitaxial growth of the first embodiment for explanation, it can be applied to the second embodiment.

In the description of the third embodiment, an example is shown in which a mask is formed directly on the substrate surface having a different lattice constant or thermal expansion coefficient from that of the GaN-based semiconductor, but after growing the GaN-based semiconductor on the substrate, Similar effects can be obtained by forming a mask on the GaN-based semiconductor surface.

Further, as the mask used in this embodiment, the same materials, dimensions and shapes as those in the first embodiment or the second embodiment can be applied. In addition, as the GaN-based semiconductor film in the present embodiment, GaN, Al
GaN, InGaN and the like can be mentioned, but GaN is most preferable.

As the GaN-based semiconductor device, GaN
In addition to GaN-based semiconductor light-emitting elements such as GaN-based LEDs and GaN-based semiconductor lasers, the present invention can be applied to devices such as FETs and HBTs.

(Fourth Embodiment) A fourth embodiment of the present invention will be described with reference to FIG.

In the fourth embodiment, a GaN-based semiconductor thick film is grown on a substrate having a different coefficient of thermal expansion and lattice constant from that of a GaN-based semiconductor by utilizing the epitaxial growth of the first embodiment. A GaN-based semiconductor device is manufactured on a GaN-based semiconductor thick film.

In the fourth embodiment, a case where a GaN-based semiconductor light emitting device is used as a GaN-based semiconductor device on a GaN-based semiconductor film will be described.

First, a mask is formed on the surface of the substrate and separated into a mask and a growth region by photolithography and wet etching. As the substrate, a substrate in which a GaN-based semiconductor is formed on a substrate material having a different thermal expansion coefficient or lattice constant from that of the GaN-based semiconductor is used.

The shapes of the mask and the growth region are as follows.
As described in the first embodiment, the shape is such that facets appear in the GaN-based semiconductor in the growth region.

Next, epitaxial growth of a GaN-based semiconductor is performed on the growth region. The method of growing a GaN-based semiconductor is based on I
Hydride VP using gallium chloride (GaCl) which is a reaction product of gallium (Ga) and hydrogen chloride (HCl) as a group II raw material and ammonia (NH ₃ ) gas as a group V raw material
The E method is preferred, but metalorganic chemical vapor deposition (MOVP)
E) may be used.

The epitaxial growth of a GaN-based semiconductor
As in the first embodiment, in the initial stage, the GaN-based semiconductor does not grow on the mask and crystal growth occurs only in the growth region, and the GaN-based semiconductor in the growth region has a plane orientation different from the plane orientation of the substrate. Is formed.

When the epitaxial growth is continued, the GaN-based semiconductor grows in a direction perpendicular to the facet structure, so that it covers not only the growth region but also the mask. Then, it comes into contact with the facet structure of the GaN-based semiconductor film in the adjacent growth region. When the epitaxial growth is further continued, the facet structure is buried with the GaN-based semiconductor, and finally, a GaN-based semiconductor film having a flat surface can be obtained.

Next, an element structure of a GaN-based semiconductor light emitting element is formed on the GaN-based semiconductor film. After forming the GaN-based semiconductor film, the substrate on which the GaN-based semiconductor film is
Set to the VD device, set the temperature, gas flow rate, V / II
I ratio, n-type GaN layer, n-type AlGaN clat layer, n
-Type GaN light guide layer, a multiple quantum well structure active layer comprising an undoped InGaN quantum well layer and an undoped InGaN barrier layer, a p-type AlGaN layer, a p-type GaN light guide layer,
A p-type AlGaN cladding layer and a p-type GaN contact layer are sequentially formed to produce a laser structure.

Next, the substrate on which the laser structure is formed is set on a polishing machine, and the substrate, the SiO ₂ mask, and a part of the GaN-based semiconductor film are polished to expose the GaN-based semiconductor film. An n-type electrode is formed on the exposed surface of the GaN-based semiconductor film, that is, a back surface of the GaN-based semiconductor light emitting element, and a p-type electrode is formed on the front surface.

The following effects can be obtained by the fourth embodiment.

By growing the GaN-based semiconductor device structure on the GaN-based semiconductor film obtained by the epitaxial growth of the first embodiment, the GaN-based semiconductor device which has been a problem in the growth using the conventional sapphire substrate is used. The crystallinity of the epitaxially grown film in the structure can be improved, and the characteristics of the GaN-based semiconductor device can be improved.

Further, when the GaN-based semiconductor device is a GaN-based semiconductor light-emitting device, an electrode can be formed on the back surface. The element can be manufactured without forming the electrode, and the electrode manufacturing process can be simplified.

When the GaN-based semiconductor light emitting device is a GaN-based semiconductor laser, a GaN-based semiconductor laser structure is formed by cleaving by removing a substrate and a mask after forming a GaN-based semiconductor thick film having few crystal defects. A mirror surface can be formed. For this reason, compared with the conventional method in which the resonator mirror surface is formed by a complicated process such as dry etching, the simplification can be greatly simplified and the yield can be greatly improved.

Note that the fourth embodiment is not limited to the above description, and other configurations and growth methods can be adopted as necessary.

For example, not only the first embodiment but also the second embodiment can be applied to epitaxial growth of a GaN-based semiconductor film.

Further, the substrate and the mask were removed after forming a stacked structure of the GaN-based semiconductor element on the GaN-based semiconductor film.
After removing a part of the system-based semiconductor film, a stacked structure of a GaN-based semiconductor element may be manufactured.

Although the example in which the substrate and the mask are removed from the GaN-based semiconductor film has been described, if it is desired to obtain only the crystallinity effect of the GaN-based semiconductor element formed on the GaN-based semiconductor film, the substrate and the mask may be removed. The electrode may be formed on the surface side of the GaN-based semiconductor element without removing GaN.

Further, as the mask used in this embodiment, the same material, size and shape as those of the first embodiment or the second embodiment can be applied. In addition, as the GaN-based semiconductor film in this embodiment, GaN, Al
GaN, InGaN and the like can be mentioned, but GaN is most preferable.

As a GaN-based semiconductor device, GaN
In addition to GaN-based semiconductor light-emitting elements such as GaN-based LEDs and GaN-based semiconductor lasers, the present invention can be applied to devices such as FETs and HBTs.

[0076]

Next, an embodiment of the present invention will be described with reference to the drawings.

(First Embodiment) An embodiment of the present invention will be described with reference to FIG. In this embodiment, a (0001) plane sapphire (Al ₂ O ₃ ) substrate 1 is used as the substrate.
A substrate on which a GaN film 12 having a thickness of about 1 μm was formed in advance was used. On the surface of the GaN film 12, SiO ₂
A film was formed, and separated into a mask 14 and a growth region 13 by photolithography and wet etching. The growth region 13 and the mask 14 are 5 μm and 2 μm, respectively.
It has a stripe shape with a width of m. Stripe direction <11
−20> direction (FIG. 1A).

The GaN film 15 grown in the growth region 13
Gallium (Ga) and hydrogen chloride (HCl) as group III raw materials
The hydride VPE method using gallium chloride (GaCl), which is a reaction product of the above, and ammonia (NH ₃ ) gas as a group V raw material was used. The substrate 11 is set in a hydride growth apparatus, and the temperature is increased to 1000 ° C. in a hydrogen atmosphere. After the growth temperature is stabilized, the HCl flow rate is increased to 20 cc /
Supplied per minute, NH ₃ flow 1000 cc / min in by supplying about 5 minutes, the GaN layer 15 in the growth region 13 {1
A facet structure composed of a -101｝ plane was grown (FIG. 1B). Further, the epitaxial growth was continued for about 20 minutes, and the facet structure 16 was developed until the mask 14 was covered (FIG. 1C).

The facet structure is buried by continuing the epitaxial growth (FIG. 1D).
G having a flat surface of about 200 μm by growth for 5 hours
An aN film was formed (FIG. 1E). After the GaN film 15 was formed, it was cooled to room temperature while supplying ammonia gas, and was taken out of the growth apparatus.

In the first embodiment, crystal growth is performed by forming facets having side walls of {1-101} by selective growth for limiting the growth region. This facet appears because the growth rate is slower than other aspects. Before the appearance of the facets, dislocations extending perpendicular to the substrate can no longer extend in this direction with the appearance of the facets.

When the crystal grown according to the present invention was examined in detail, it was found that with the appearance of the facet, the crystal was bent in the lateral direction and emerged at the edge of the crystal as the thickness of the epitaxial film increased. As a result, defects in the epitaxial film can be reduced.

It was confirmed that the GaN film 15 formed according to the first embodiment had no cracks despite the difference in lattice constant and coefficient of thermal expansion from the sapphire substrate 11. Moreover, the GaN film grown by the thick film had very few defects, and the defect density was about 10 ⁶ cm ² .

The GaN film grown in this embodiment has very few defects. By growing a high-quality device structure such as a laser, FET, and HBT on the GaN film, it is possible to improve device characteristics. .

Further, by removing the sapphire substrate 11 by polishing or the like, the GaN film 15 can be used as a substrate material.

In the first embodiment, the GaN film is formed by using the hydride VPE method for the epitaxial growth.
A similar effect can be obtained by using an organometallic compound vapor deposition method (MOCVD). Although the Al ₂ O ₃ substrate 11 was used, a Si substrate, a ZnO substrate, a SiC substrate, a LiGaO ₂
Similar effects can be obtained by using a substrate, a MgAl ₂ O ₄ substrate, or the like. Further, although the GaN film 12 is formed on the Al ₂ O ₃ substrate 11 in advance, a mask may be formed directly on the substrate 11.

Although the mask 14 is made of SiO ₂ , the present invention is not limited to this, and an insulator film such as SiN _x may be used. In this embodiment, the width of the mask 14 is 2 μm. However, the same effect can be obtained as long as the width of the mask 14 can be embedded. Further stripes <11-20>
However, if a facet is formed, the facet may be formed in a direction <1-100> perpendicular to the facet. Even if the facet is inclined at an angle from these directions, a facet structure is formed in the growth region depending on the conditions of crystal growth. can do. Note that the conditions for crystal growth for forming the facet structure differ depending on the material.

Although the epitaxial growth of GaN has been described, the same effect can be obtained by epitaxially growing an InGaN film, an AlGaN film, and an InN film. Similar effects can be obtained by adding impurities to the growing group III-V compound.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIG. 1 as in the first embodiment.

In the second embodiment, (000
1) Al _{0.1 having a} thickness of about 1 μm on the surface SiC substrate 11
A crystal on which a Ga _0.9 N film 12 was formed in advance was used. The surface of the Al _0.1 Ga _0.9 N film 12 is SiO ₂
A film was formed, and separated into a mask 14 and a growth region 13 by photolithography and wet etching. The growth region 13 and the mask 14 are 2 μm and 1 μm, respectively.
It has a stripe shape with a width of 0 μm. The stripe direction is <
1-100> direction ((FIG. 1A)).

The GaN film 15 grown in the growth region 13 is
Gallium (Ga) and hydrogen chloride (HCl) as group III raw materials
The hydride VPE method using gallium chloride (GaCl), which is a reaction product of the above, and ammonia (NH ₃ ) gas as a group V raw material was used. The substrate 11 is set in a hydride growth apparatus, and the temperature is increased to 1000 ° C. in a hydrogen atmosphere. After the growth temperature is stabilized, the HCl flow rate is increased to 20 cc /
Supplied per minute, NH ₃ flow rate 2000cc / min in by supplying about 5 minutes, the GaN layer 15 in the growth region 13 {1
A facet structure composed of a -101｝ plane was grown (FIG. 1B).

Further, the epitaxial growth was continued for about 20 minutes, and the facet structure 15 of GaN was developed until the mask 14 was covered (FIG. 1C).

The facet structure is buried by continuing the epitaxial growth (FIG. 1 (d)).
G having a flat surface of about 200 μm by growth for 5 hours
An aN film was formed (FIG. 1E). After the GaN film 15 is formed, it is cooled at room temperature while supplying NH ₃ gas, and taken out from the growth apparatus.

It was confirmed that the GaN film 15 formed by the second embodiment had no cracks despite the difference in the lattice constant and the coefficient of thermal expansion from the SiC substrate 11. Moreover, the GaN film grown by the thick film had very few defects and a defect density of about 10 ⁶ cm ² .

The GaN film grown in this example has very few defects. By growing a high-quality device structure such as a laser, FET, and HBT thereon, it is possible to improve device characteristics. .

Further, the GaN film 15 can be used as a substrate material by removing the SiC substrate 11 by polishing or the like.

In the second embodiment, the GaN film is formed by using the hydride VPE method for the epitaxial growth.
A similar effect can be obtained by using an organometallic compound vapor deposition method (MOCVD). In this embodiment, the SiC substrate 1
However, similar effects can be obtained by using a Si substrate, a ZnO substrate, an Al ₂ O ₃ substrate substrate, a LiGaO ₂ substrate, a MgAl ₂ O ₄ substrate, or the like. Furthermore, SiC substrate 1
Although the GaN film 12 having a thickness is formed on the substrate 1 in advance, a mask may be formed directly on the substrate 11.

Although SiO ₂ is used as the mask 14, the present invention is not limited to this, and an insulator film such as SiN _x may be used. In this embodiment, the width of the mask 14 is 10 μm.
However, the same effect can be obtained as long as the mask can be embedded. Further stripes <1-100
However, if a facet is formed, the facet may be formed in a direction <1-120> perpendicular to the facet. Even if the facet is inclined at an angle from these directions, the facet structure is formed in the growth region depending on the conditions of crystal growth. Can be formed. Note that the conditions for crystal growth for forming the facet structure differ depending on the material.

Further, although AlGaN having an Al composition of 0.1 was used as the film on the substrate 11, the composition may be arbitrary, and similar effects can be obtained by using AlN, InGaN or the like as this film. Can be Furthermore, the epitaxial growth of GaN was described.
Similar effects can be obtained by epitaxially growing a GaN film or an InN film. Similar effects can be obtained by adding an impurity to the growing group III-V compound.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIG.

In the third embodiment, (11)
The MgAl ₂ O ₄ substrate 21 having the 1) surface was used. An SiO ₂ film 23 was formed on the surface of the substrate 21 and separated into a mask 23 and a growth region 22 by photolithography and wet etching. The growth region 22 and the mask 23
Each has a stripe shape with a width of 4 μm and 3 μm. The stripe direction was the <11-20> direction (FIG. 2A).

The GaN film is grown by using a hydride VP suitable for suppressing the adhesion of polycrystalline GaN on the mask 23.
Method E was used. In this method, gallium chloride (GaCl) which is a reaction product of gallium (Ga) and hydrogen chloride (HCl) is used as a group III raw material, and ammonia (NH) is used as a group V raw material.
₃ ) Use gas.

First, the substrate 21 was set in a growth apparatus, heat-treated at a high temperature of about 1000 ° C. while supplying hydrogen gas, and then cooled to 500 ° C., and the HCl flow rate was set to 0.5 cc / cc.
The GaN buffer layer 24 having a thickness of about 20 nm is formed in the crystal growth region 23 by supplying the GaN buffer layer 24 at a rate of 1000 cc / min for about 5 minutes at a flow rate of NH _{3 of} FIG.
(B)).

In this state, while supplying NH ₃ gas, 1
Raise the temperature to 000 ° C. After the growth temperature is stabilized, HCl
The flow rate is supplied at 20 cc / min, and the NH ₃ flow rate is 1500
By supplying cc / min for about 5 minutes, a facet structure 25 made of GaN {1-101} plane was grown on the GaN buffer layer 24 in the growth region 22 (FIG. 2).
(C)).

Further, after the epitaxial growth is continued and the facet structure of the GaN film 25 is developed until the mask 23 is covered, the growth is continued while the facet structure is buried, and finally a flat surface of about 200 μm is grown by 5 hours. A GaN film 25 having a surface was formed (FIG. 2).
(D)). After the formation of the GaN film 25, it is cooled to room temperature while supplying NH ₃ gas and taken out from the growth apparatus.

It was confirmed that the GaN film 25 formed by the third embodiment had no cracks despite the difference in lattice constant and coefficient of thermal expansion from the MgAl ₂ O ₄ substrate 21. Moreover, the GaN film grown by the thick film had very few defects and was about 10 ⁶ cm ² .

The GaN film grown in this example has very few defects, and by growing a high-quality device structure such as a laser, FET, and HBT thereon, device characteristics can be improved. . MgAl ₂ O ₄
By removing the substrate 21 by polishing or the like, the GaN film 25 can be used as a substrate material.

In the third embodiment, the GaN film is formed by using the hydride VPE method for epitaxial growth.
A similar effect can be obtained by using an organometallic compound vapor deposition method (MOCVD). Further, in the embodiment, MgAl ₂ O ₄
The substrate 21 was used, but the Si substrate, the ZnO substrate, the SiC
Similar effects can be obtained by using a substrate, a LiGaO ₂ substrate, an Al ₂ O ₃ substrate, or the like. Further, MgAl ₂ O ₄ 21
Although the mask is formed directly on the substrate, a GaN film may be formed on the substrate 21 in advance.

Although SiO ₂ is used as the mask 14, the present invention is not limited to this, and an insulator film such as SiN _x may be used. Further, although the width of the mask 24 is set to 10 μm, the same effect can be obtained as long as the mask can be embedded. In this embodiment, the stripe is set to <11-2.
0> direction, but if a facet is formed, it may be a direction <1-100> perpendicular to the facet, or a facet structure is formed in the growth region even at an angle inclined from these directions according to crystal growth conditions. be able to. The crystal growth conditions for forming the facet structure differ depending on the material.

In this embodiment, since the GaN film is grown after the low-temperature buffer layer is provided on the substrate, it is possible to further reduce crystal defects.

Further, in the examples, the epitaxial growth of GaN has been described.
Similar effects can be obtained by epitaxially growing a film or InN film. Similar effects can be obtained by adding impurities to the growing group III-V compound.

(Fourth Embodiment) A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a schematic view showing a growth region for selectively epitaxially growing a circular, triangular, and rectangular shape.

In this embodiment, a GaN film having a thickness of about 1 μm is formed on a (0001) plane Al ₂ O ₃ substrate 41 as a substrate.
A crystal substrate on which the film 42 was formed in advance was used.

An SiO ₂ film was formed on the surface of the GaN film 42 and separated into a mask 43 and a growth region 44 by photolithography and wet etching. Growth area 44
Is a circle having a diameter of 4 μm (FIG. 3A), and a side of 3 μm
3 (FIG. 3 (b)) and three types of masks (5 μm square (FIG. 3 (c))).

The GaN film 45 grown in the formed growth region 44 is made of trimethylgallium (TMG
a) and an organometallic compound vapor deposition method using ammonia (NH ₃ ) gas as a trimethyl aluminum (TMAl) and a group V raw material.

FIG. 4 is a schematic diagram showing a process of forming a group III-V compound semiconductor film by vapor phase growth on the substrate on which the growth region of FIG. 3 is formed. The substrate 41 is set in the organometallic compound vapor phase epitaxy apparatus, and the temperature is increased to 1050 ° C. while supplying hydrogen gas and NH ₃ gas. After the growth temperature is stabilized, trimethylgallium is supplied at a flow rate of 5 cc / min and NH ₃ flow is supplied at a rate of 5000 cc / min for about 10 minutes.
A facet structure composed of a -101｝ plane was grown (FIG. 4A).

Further, the epitaxial growth was continued for about 30 minutes, and the facet structure of the GaN layer 45 was developed until the mask 43 was covered (FIG. 4B).

By continuing epitaxial growth, G
The facet structure of the aN layer 45 is embedded (FIG.
(C)) Finally, a GaN film 45 having a flat surface of about 100 μm was formed by growth for 12 hours (FIG. 4D).

GaN formed in growth regions of three different shapes
The film 45 had a flat surface regardless of the shape of the growth region, and it was confirmed that the sapphire substrate 41 had no crack. Further, in the present embodiment, the growth region has three shapes, that is, a round shape, a triangular shape, and a rectangular shape. However, any shape that can embed the mask region has the same shape regardless of the polygonal shape and size. effective.

The GaN film grown in this example has very few defects. By growing a high-quality device structure such as a laser, an FET, and an HBT on the GaN film, the device characteristics can be improved. .

Further, by removing the sapphire substrate 41 by polishing or the like, the GaN film 45 can be used as a substrate material.

In the fourth embodiment, the GaN film is formed by using the hydride VPE method for epitaxial growth.
A similar effect can be obtained by using an organometallic compound vapor deposition method (MOCVD). Although the Al ₂ O ₃ substrate 41 was used, a Si substrate, a ZnO substrate, a SiC substrate, and a LiGaO substrate were used.
_A similar effect can be obtained by using a _two- substrate, a MgAl ₂ O ₄ substrate, or the like. Further, although the GaN film 42 having a thickness is formed in advance on the Al ₂ O ₃ substrate 41, a mask may be formed directly on the substrate 41.

Although SiO ₂ is used as the mask 43, the present invention is not limited to this, and an insulator film such as SiN _x may be used.

Although the GaN epitaxial growth has been described, the same effect can be obtained by epitaxially growing an InGaN film, an AlGaN film, or an InN film. Similar effects can be obtained by adding impurities to the growing group III-V compound.

(Fifth Embodiment) A fifth embodiment of the present invention will be described with reference to FIG.

A GaN film 5 having a thickness of 1 μm is formed on the substrate 51.
The sapphire substrate 51 of (0001) plane on which No. 2 was formed was used.

An SiO ₂ film was formed on the surface of the substrate 51, and separated into a first mask 53 and a first growth region by photolithography and wet etching. First
The growth region 54 and the first mask 53 were formed in a stripe shape of 2 μm and 5 μm, respectively. The stripe direction was <11-20> (FIG. 5A).

First Ga grown in first growth region 54
The N film 55 is formed by adding gallium chloride (GaCl) which is a reaction product of gallium (Ga) and hydrogen chloride (HCl) to the group III raw material and ammonia (NH ₃ ) gas to the group V raw material as in the first embodiment. The hydride VPE method used was used. The substrate 51 is set in a hydride growth apparatus, and the temperature is increased to 1000 ° C. in a hydrogen atmosphere. The substrate 51 is set in an NH ₃ gas atmosphere at a temperature of 650 ° C. After the growth temperature was stabilized, HCl was supplied at a flow rate of 10 cc / minute, and NH ₃ flow was grown at 4000 cc / minute for 60 minutes. After the growth step of (1), a first GaN film 55 in which the first mask 53 is embedded is formed (FIG. 5B). First GaN
After forming the film 55, the film 55 is cooled to room temperature in an NH ₃ gas atmosphere,
Remove from growth device.

Next, an SiO ₂ film is formed again on the GaN film 55, and a second growth region 56 and a second mask 57 are formed. Each stripe width is 2 μm, and 5
μm, and the stripe direction was <11-20> (FIG. 5C). A second mask 57 is buried on this substrate 51 again through the growth steps of FIGS. 1A to 1E described in the first embodiment, and a second GaN layer 58 of about 150 μm is formed. The grown and flattened surface was obtained (FIG. 5D).

As a result of examining a defect of the grown second GaN film 58 by a cross-sectional transmission electron microscope, it was found that the defect was as extremely small as 10 ⁵ cm ² or less. Here, the two-stage selective growth has been described, but the defect density can be further reduced by repeating the above steps.

In the fifth embodiment, the GaN film is formed by using the hydride VPE method for epitaxial growth.
A similar effect can be obtained by using an organometallic compound vapor deposition method (MOCVD). Although the Al ₂ O ₃ substrate 51 was used, a Si substrate, a ZnO substrate, a SiC substrate, and a LiGaO substrate were used.
_A similar effect can be obtained by using a _two- substrate, a MgAl ₂ O ₄ substrate, or the like. Further, GaN is formed on the Al ₂ O ₃ substrate 51.
Although the mask is formed after growing the film 52, the invention is not limited to this, and the first mask 53 may be directly grown without growing the GaN film 52 on the substrate.

Although SiO ₂ is used as the mask 53, the present invention is not limited to this, and an insulator film such as SiN _x may be used. Furthermore, although a mask patterned so that the growth region becomes a stripe is used, the present invention is not limited to this and may be a round shape, a rectangular shape, or a triangular shape. Also, the epitaxial growth of GaN was described.
Similar effects can be obtained by epitaxially growing an N film or an InN film. Similar effects can be obtained by adding impurities to the growing group III-V compound.

In each embodiment of the present invention, a GaN-based III-
Although an example using a group V compound semiconductor has been described, the present invention is not limited to this, and it is needless to say that the present invention can be applied to the growth of a group III-V compound semiconductor having a different lattice constant or thermal expansion coefficient from the substrate. .

(Sixth Embodiment) A sixth embodiment of the present invention will be described with reference to FIG. FIG. 6 shows that the epitaxial growth of the present invention is used for the growth of a GaN film.
FIG. 4 is a schematic diagram for explaining a step of manufacturing a GaN-based semiconductor laser on an aN film.

As the substrate 61 shown in FIG. 6, a (0001) plane sapphire substrate 61 on which a GaN film 62 having a thickness of 1 μm was formed was used. An SiO ₂ film is formed on the surface of the substrate 61, and the first mask 63 and the first mask 63 are formed by photolithography and wet etching as in the first to fourth embodiments.
In the growth region 64. The first growth region 64 and the first mask 63 are 5 μm and 2 μm, respectively.
Stripes. The stripe direction is <11-2.
It was formed at an angle of 10 degrees from the 0> direction (FIG. 6A).

First Ga grown in first growth region 64
In the same manner as in the first embodiment, gallium chloride (GaCl), which is a reaction product of gallium (Ga) and hydrogen chloride (HCl), and ammonia (NH ₃ ) gas as a group V material are used for the N film 65. The hydride VPE method used was used. The substrate 61 is set in a hydride growth apparatus, and heated to a growth temperature of 1000 ° C. in a hydrogen atmosphere. The substrate 51 is set in an NH ₃ gas atmosphere at a temperature of 650 ° C. After the growth temperature was stabilized, HCl was supplied at a flow rate of 40 cc / min, and growth was performed at an NH ₃ flow rate of 1000 cc / min and a silane (SiH ₄ ) flow rate of 0.01 cc / min for 150 minutes. Through the growth steps of FIGS. 1A to 1E described in the embodiment, a 200 μm-thick first GaN film 65 embedded with a first mask 63 is formed (FIG. 5B). After forming the first GaN film 65, it is cooled to room temperature in an NH ₃ gas atmosphere and taken out from the growth apparatus. G
The aN film 65 was n-type and had a carrier concentration of 1 × 10 ¹⁸ cm ⁻³ or more.

Next, a GaN-based semiconductor laser structure was manufactured by using metal organic chemical vapor deposition (MOVPE). After forming the GaN film 65, it is set in a MOCVD apparatus, and the temperature is increased to 1050 ° C. in a hydrogen atmosphere. 6
The temperature is changed from 50 ° C. to an NH ₃ gas atmosphere. 1 μm thick n-type GaN layer 66 to which Si is added, 0.4 μm thick n-type Al _0.15 Ga _0.85 N clat layer 67 to which Si is added, 0.1 μm thick n-type layer to which Si is added GaN
Light guide layer 68, undoped In with a thickness of 2.5 nm
_0.2 Ga _0.8 N quantum well layer and 5 nm thick undoped I
An active layer 69 having a multi-quantum well structure having 10 periods composed of an n _0.05 Ga _0.95 N barrier layer and magnesium (Mg) added 2
A p-type Al _0.2 Ga _0.8 N layer 70 having a thickness of 0 nm, a p-type GaN optical guide layer 71 having a thickness of 0.1 μm to which Mg is added,
0.4 μm thick p-type Al _0.15 Ga doped with Mg
_{A 0.85} N cladding layer 72 and a 0.5 μm-thick p-type GaN contact layer 73 to which Mg was added were sequentially formed to form a laser structure. After the formation of the p-type GaN contact layer 73, it is cooled to room temperature in an HN ₃ gas atmosphere and taken out from the growth apparatus (FIG. 6C). The multiple quantum well structure active layer 69 composed of an undoped In _0.2 Ga _0.8 N quantum well layer having a thickness of 2.5 nm and an undoped In _0.05 Ga _0.95 N barrier layer having a thickness of 5 nm was formed at a temperature of 780 ° C.

Next, the sapphire substrate 61 on which the laser structure was formed was set in a polishing machine, and the sapphire substrate 61, G
aN layer 62, SiO ₂ mask 63, and GaN film 6
5 is polished to 50 μm to expose the GaN film 65. On the surface of the exposed GaN layer 65, titanium (Ti) -aluminum (A
1) An n-type electrode 74 is formed, and a nickel (Ni) -gold (Au) p-type electrode 75 is formed on the p-type GaN layer 73 (FIG. 6D).

In the laser structure shown in FIG. 6, an n-type electrode is formed on the back surface, and an element can be formed without forming an n-type electrode on the nitride surface by a complicated manufacturing process such as dry etching. Therefore, the electrode manufacturing process can be simplified.

In addition, since sapphire and GaN-based semiconductors have different cleavage planes of crystals, it has been difficult to form a resonator mirror having a laser structure conventionally formed on a sapphire substrate by cleavage.

On the other hand, in the present embodiment, since the GaN layer 65 having few crystal defects can be grown thick, the GaN-based semiconductor laser structure formed on the GaN 65 can be formed even if the sapphire substrate or the mask material is removed. There is no effect, and the laser structure on the GaN layer 65 has the advantage that the cavity mirror surface can be formed by cleavage, and is significantly larger than the cavity mirror surface formed by a complicated process such as conventional dry etching. The yield was greatly improved.

In this embodiment, after forming a laser structure on the GaN layer 65, the sapphire substrate 51, the GaN film 6
2. Although the SiO ₂ mask 63 was polished, the sapphire substrate 61, GaN film 62, Si
The same effect can be obtained by polishing the O ₂ mask 63.

In this embodiment, the sapphire substrate 6
1. Polishing of the GaN layer 62 and the SiO ₂ mask 63 and polishing of a part of the GaN film 65 to form an n-type electrode.
By removing the aN layer 66 or 65 to form an n-type electrode and forming a resonator mirror surface, a conventional structure can be manufactured.

[0143]

As described above, according to the present invention, II
A method for growing an IV group compound semiconductor includes an initial growth stage,
By limiting the growth region on the substrate by the mask and promoting facet growth, cracks caused by a difference in thermal expansion coefficient and a difference in lattice constant between the growing III-V compound semiconductor layer and the substrate crystal are suppressed, and the introduction of defects is suppressed. Suppression can form a high-quality III-V compound semiconductor layer. Therefore, when the crystal according to the present invention is used, a high-quality semiconductor element, for example, a laser structure or a transistor structure can be manufactured thereon, and its characteristics are expected to be dramatically improved.

[Brief description of the drawings]

FIG. 1 is a schematic process diagram illustrating a method for forming a group III-V compound semiconductor of the present invention.

FIG. 2 is a schematic view of a step of forming a GaN film on a MgAl ₂ O ₄ substrate on which an AlGaN film is formed by using a hydride VPE method.

FIG. 3 is a schematic diagram in which a growth region selectively epitaxially grown is formed into a round shape, a triangular shape, and a rectangular shape.

FIG. 4 is a schematic diagram of a step of forming a group III-V compound semiconductor film by using a vapor phase growth method on a substrate on which the round, triangular, and rectangular growth regions of FIG. 3 are formed.

FIG. 5 shows a G formed by repeating the growth method of the present invention twice.
FIG. 3 is a schematic view of an aN film.

FIG. 6 is a schematic view of a step of forming a GaN-based semiconductor laser structure on a GaN film formed by using the growth method of the present invention.

[Explanation of symbols]

Reference Signs List 11 substrate 12 III-V compound semiconductor film formed on substrate 13 growth region for growing III-V compound semiconductor 14 mask 15 epitaxially grown III-V compound semiconductor film 16 facet structure of III-V compound semiconductor 21 (0001) plane sapphire substrate 22 GaN film 23 mask 25 epitaxially grown GaN film 31 (111) MgAl ₂ O ₄ substrate 32 1 μm GaN film or AlGaN film 32 growth region formed on substrate 33 substrate Mask of formed SiO ₂ film 34 Epitaxially grown GaN buffer layer 35 GaN film grown by hydride VPE method 43 Mask 44 Growth region 51 Sapphire substrate of (0001) plane 53 First mask 54 First growth region 55 First GaN layer 56 2 growth areas 57 a second mask 58 second GaN layer 65 n-type GaN layer 66 n-type GaN layer 67 n-type Al _0.15 Ga _0.85 N Klatt layer 68 n-type GaN optical guide layer 69 10 cycles of multi-quantum well structure Active layer 70 p-type Al _0.2 Ga _0.8 N layer 71 p-type GaN optical guide layer 72 p-type Al _0.15 Ga _0.85 N clat layer 73 p-type GaN contact layer 74 Ti-Al n-type electrode 75 Ni-Au p-type electrode

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-11-135770 (JP, A) JP-A-6-163930 (JP, A) JP-A-12-12976 (JP, A) JP-A-11-135 31864 (JP, A) JP-A-56-59699 (JP, A) JP-A-4-127521 (JP, A) International publication 97/11518 (WO, A1) IEEJ Technical Report (1991.11.11) OQD-91-56, Optical and Quantum Workshop, Jpn. J. Appl. Phys Part. 236 [7B] (1997) p. L 899-902 (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/205 H01S 5/00 C30B 25/00 C30B 29/00 C23C 16/00 H01L 33/00

Claims (19)

(57) [Claims] In the epitaxial growth of a GaN-based semiconductor, a step of forming a growth region using a mask material patterned on a substrate surface, and a facet structure of a GaN-based semiconductor having a lattice constant and a thermal expansion coefficient different from those of the substrate in the growth region And growing the GaN-based semiconductor in a facet structure of the GaN-based semiconductor in an adjacent growth region and flattening the surface by covering the mask material. 2. The method for growing a GaN-based semiconductor according to claim 1, wherein the steps are repeated on the flattened surface. 3. The patterned mask after forming a GaN-based semiconductor having the same material as the GaN-based semiconductor grown in the growth region or having a similar lattice constant or thermal expansion coefficient on the substrate surface. 3. The method for growing a GaN-based semiconductor according to claim 1, wherein a growth region formed of a material is formed. 4. The GaN-based semiconductor according to claim 1, wherein a growth region formed using the mask material has a stripe shape, a rectangular shape, a round shape, or a triangular shape. Growth method. 5. The method according to claim 1, wherein the substrate is a MgAl ₂ O ₄ substrate, a Si substrate, a ZnO substrate, a SiC substrate, a LiGaO ₂ substrate, or an Al ₂ O ₃ substrate.
Selected from any one of O ₃ substrates, wherein the GaN-based semiconductor is any one of GaN, InGaN, and AlGaN.
5. The method of growing a GaN-based semiconductor according to claim 1, wherein the method is selected from the group consisting of: 6. The GaN-based semiconductor includes GaN, InG
aN, selected from any one of AlGaN, and
4. The method of growing a GaN-based semiconductor according to claim 1, wherein a shape of the mask is a stripe shape, and a side wall of the facet structure is a {1-101} plane. 5. 7. The GaN-based semiconductor may be GaN, InG
aN, selected from any one of AlGaN, and
4. The growth of the GaN-based semiconductor according to claim 1, wherein the mask has a stripe shape, and a stripe direction is a <11-20> direction or a <1-100> direction. Method. 8. A GaN-based semiconductor, comprising: after forming the GaN-based semiconductor according to claim 1, removing at least the substrate and a mask material from the GaN-based semiconductor. Growth method. 9. A method for growing a GaN-based semiconductor, comprising a step of growing a device structure after forming the GaN-based semiconductor according to claim 1. 10. The method according to claim 1, wherein the device structure is a laser, a FET,
10. The method for growing a GaN-based semiconductor according to claim 9, wherein the method is any one of HBT. 11. A substrate having a lattice constant and a thermal expansion coefficient different from those of a GaN-based semiconductor, a mask material patterned to form a growth region on the surface of the substrate, and a GaN-based material grown while forming a facet structure in the growth region. A GaN-based semiconductor, comprising a GaN-based semiconductor formed by embedding the facet structure by growing the GaN-based semiconductor and covering the mask material with the growth of the GaN-based semiconductor in an adjacent growth region. film. 12. The GaN-based semiconductor film according to claim 11, wherein at least the substrate and the mask material are removed from the GaN-based semiconductor film. 13. A GaN-based semiconductor having the same material as the GaN-based semiconductor grown in the growth region or having a property similar to a lattice constant or a thermal expansion coefficient is formed on the substrate surface. 13. The GaN-based semiconductor film according to claim 11, wherein a growth region is formed by using a mask material. 14. The GaN-based semiconductor film according to claim 11, wherein a growth region formed by using said mask material has a stripe shape, a rectangular shape, a round shape, or a triangular shape. . 15. The substrate is a MgAl ₂ O ₄ substrate, Si
Substrate, ZnO substrate, SiC substrate, LiGaO ₂ substrate, A
The GaN-based semiconductor is selected from any one of l ₂ O ₃ substrates, and the GaN-based semiconductor is selected from any one of GaN, InGaN, and AlGaN.
5. The GaN-based semiconductor film according to any one of 4. 16. The GaN-based semiconductor comprises GaN, In
14. The semiconductor device according to claim 11, wherein the mask is selected from one of GaN and AlGaN, and the shape of the mask is a stripe shape, and a side wall of the facet structure is a {1-101} plane. Ga described in any of
N-based semiconductor film. 17. The GaN-based semiconductor may be GaN, In
The mask is selected from one of GaN and AlGaN, and the mask has a stripe shape, and the stripe direction is a <11-20> direction or a <1-100> direction.
14. The GaN-based semiconductor film according to claim 11, wherein the direction is a direction. 18. A GaN-based semiconductor device, wherein a device structure is formed on the GaN-based semiconductor film according to claim 11. 19. The device according to claim 19, wherein the device structure is a laser, a FET,
The GaN-based semiconductor device according to claim 18, wherein the GaN-based semiconductor device is any one of HBT.