JP2001007394A - Semiconductor substrate, manufacture thereof and semiconductor light emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a large-area and high-quality industrially practicable GaN semiconductor substrate, a manufacturing method thereof and a semiconductor light emitting element. SOLUTION: An InrAlsGa1-r-sN (0<=r<=1, 0<=s<=1, r+s<=1) single-crystal film 52 is formed on a first substrate 50, pasted on a second substrate 53 having approximately the same thermal expansion coefficient as that of the InrAlsGa1-r-sN (0<=r<=1, 0<=s<=1, r+s<=1) single crystal and separated from the first substrate 50, an InxAlyGa1-x-yN (0<=x<=1, 0<=y<=1, x+y<=1) single crystal 54 is epitaxially grown on the InrAlsGa1-r-sN single crystal film 52, this film 52 pasted on the second substrate 53, and the InxAlyGa1-x-yN single crystal 54 is separated from the second substrate 53.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor substrate used for a light source for an optical pickup such as a DVD or a CD, a method of manufacturing the same, and a semiconductor light emitting device.

[0002]

2. Description of the Related Art Conventionally, a blue LED has low brightness compared to red and green, and has been difficult to put into practical use. However, in recent years, a low-temperature AlN buffer layer or a low-temperature Improvement of crystal growth technology by using a GaN buffer layer and Mg
By obtaining a low-resistance p-type semiconductor layer doped with, a high-intensity blue LED was put to practical use, and a semiconductor laser that did not reach practical use but continually oscillated at room temperature was realized.

In general, when a high-quality semiconductor layer is epitaxially grown on a substrate, it is necessary that the substrate and the semiconductor layer have substantially the same lattice constant and thermal expansion coefficient. However, there is no GaN-based semiconductor that satisfies these requirements at the same time. At present, attempts have been made to produce bulk GaN single crystals, but in reality, only a few millimeters have been obtained, and it is far from practical use. Therefore, in general, sapphire,
It is grown on a substrate whose lattice constant and coefficient of thermal expansion are significantly different from those of GaN-based semiconductors such as MgAl ₂ O ₄ spinel and SiC. Therefore, in the case of a GaN-based semiconductor, in order to manufacture a semiconductor laser that requires a high-quality crystal layer,
Techniques have been used to suppress the occurrence of crystal defects due to differences in lattice constant and coefficient of thermal expansion between the substrate and the semiconductor laser crystal.

FIG. 12 shows a document "Applied Physics Letter".
s Vol. 72 (1998) P. 211 "is a cross-sectional view of a conventional edge-emitting semiconductor laser, and the semiconductor laser of FIG. 12 is one of the ones using the above-described technique. The conventional semiconductor laser shown in FIG. 12 is formed on a low-defect substrate manufactured by combining selective growth and lateral growth.

That is, the semiconductor laser shown in FIG. 12 is manufactured by the following method. First, thickness 100-300
sapphire (Al ₂ O ₃
On a (single-crystal) substrate 111, a low-temperature buffer layer 112 made of n-type GaN and a high-temperature buffer layer 1 made of n-type GaN
Grow 13. Next, SiO ₂ is deposited on the surface of the n-type GaN layer 113, a stripe pattern is opened, and a selective growth mask 114 is formed. Next, GaN is selectively grown on the surface of the GaN layer 113 exposed from the mask. Further, the growth is continued, lateral growth is performed on the mask surface, and finally an n-type GaN single crystal layer having a thickness of about 20 μm is formed, thereby forming a semiconductor laser crystal growth substrate.

The semiconductor laser structure has an n-In
_0.1 Ga _0.9 N crack prevention layer 115, n-Al _0.14 Ga
_0.86 N / GaN MD-SLS (modulation doped strained superlattice) cladding layer 116, n-GaN optical guide layer 117, In _0.15 Ga _0.85 N / In _0.02 Ga _0.98 N
MQW active layer 118, p-Al _0.2 Ga _0.8 N dislocation propagation prevention layer 119, p-GaN layer light guide layer 120, p-Al
_0.14 Ga _0.86 N / GaN MD-SLS clad layer 12
The cap layer 122 made of a 1, p-type GaN layer is an MOCV
The layers are sequentially stacked by the D method. An optical waveguide and an optical resonator end face are formed by dry-etching the stacked semiconductor layers in a ridge shape, and further, the n-GaN layer 113 exposed by etching and a cap layer which is a surface layer of the stacked semiconductor layers. A semiconductor laser is formed by providing an n-side electrode 125 and a p-side electrode 123 at 122, respectively.

With the development of a technique for forming a semiconductor laser on a low-defect substrate manufactured by combining selective growth and lateral growth shown in FIG. 12, the lifetime of a semiconductor laser at room temperature continuous oscillation is estimated to be near room temperature and low power. It has been extended to about 10,000 hours. Specifically, GaN having such a structure
The lifetime of continuous oscillation at 20 ° C. and 2 mW is extended to about 10,000 hours by the system semiconductor laser.

However, the conventional Ga shown in FIG.
Since a light emitting device using an N-based compound semiconductor layer grows on a heterogeneous substrate having a different crystal structure, the cleavage planes of the substrate and the GaN-based compound semiconductor do not always coincide with each other. It is difficult to perform the cleavage by a cleavage method such as a laser of AlGaAs type.

In the conventional example shown in FIG. 12, the end face of the optical resonator is manufactured by a method such as dry etching. For this reason, the manufacturing process is complicated because it requires steps such as formation of a dry etching mask, dry etching, and removal of the mask. Furthermore, since a dry etching technique for a GaN-based compound semiconductor has not yet been established, the formed resonator mirror has vertical streaks and irregularities, and is formed in a tapered shape. Sex and verticality were not yet enough. Further, when the resonator mirror was formed by dry etching, the substrate remained as a terrace in front of the end face of the resonator mirror, so that light was reflected by this terrace, and the beam shape did not become a single peak.

In a conventional light emitting device using a GaN-based compound semiconductor formed on a sapphire substrate, an electrode cannot be formed from the back surface of the substrate because the sapphire substrate is insulative. Therefore, the electrodes are formed on the surface of the element, so that the electrodes cannot be formed on the back surface of the substrate and mounted by die bonding as in a conventional AlGaAs-based laser, and the chip area is reduced by the space of the electrodes. The problem of becoming larger still remained. Further, due to the poor thermal conductivity of the sapphire substrate, the lifetime was extremely short in high-temperature operation or high-power operation.

Regarding a GaN-based laser device on a substrate other than a sapphire substrate, a (0001) c-plane SiC substrate and (11)
1) It has been reported that a MgAl ₂ O ₄ substrate is used. However, when a SiC substrate is used, cracks occur during crystal growth due to a difference in thermal expansion coefficient between SiC and a GaN-based semiconductor, and a sufficient thickness for a laser structure is obtained. However, it is difficult to form a laminated structure having such a structure, and continuous oscillation at room temperature has not been achieved. Also, (1
11) When a MgAl ₂ O ₄ substrate is used, an electrode cannot be formed on the back surface of the substrate because the substrate is insulating like sapphire.

The Ga formed on such a dissimilar material substrate
In order to solve the problems of the N-based semiconductor laser, there has been reported that a GaN-based semiconductor laser was manufactured by separating a GaN-based semiconductor layer crystal-grown on a sapphire substrate from the substrate and manufacturing a GaN substrate.

FIG. 13 shows a document "Jpn.J.Appl.Phys.Vol.37".
(1998) pp. L309-L312 "is a cross-sectional view of a conventional edge-emitting semiconductor laser shown in FIG. 13, and the semiconductor laser of FIG. 13 has a laser structure similar to that of FIG. 12 formed on a GaN substrate. It is a thing.

That is, the semiconductor laser shown in FIG.
A high-temperature buffer layer 132 made of n-type GaN and an n-In _0.1 Ga _0.9 N crack prevention layer 13 are formed on a substrate 131 made of GaN having a (001) plane as a main surface and having a thickness of 80 μm.
3, n-Al _0.14 Ga _0.86 N / GaN MD-SLS
(Modulation doped strained superlattice) Cladding layer 13
4, n-GaN optical guide layer 135, In _0.15 Ga _0.85 N
/ In _0.02 Ga _0.98 N MQW active layer 136, p-Al
_0.2 Ga _0.8 N dislocation propagation prevention layer 137, p-GaN layer light guide layer 138, p-Al _0.14 Ga _0.86 N / GaN MD
-An SLS cladding layer 139 and a cap layer 140 made of a p-type GaN layer are sequentially laminated by MOCVD. An optical waveguide is formed by dry-etching the laminated semiconductor layer in a ridge shape, and further,
A semiconductor laser is formed by providing an n-side electrode 143 and a p-side electrode 141 on the n-GaN layer 132 exposed by etching and the cap layer 140 which is a surface layer of the stacked semiconductor layers, respectively. The laser cavity mirror is made by cleavage.

As described above, the GaN substrate shown in FIG.
On the low-defect substrate of the semiconductor laser shown in FIG. 2, a GaN layer of about 1 was used instead of the stacked structure 115 to 122 of the semiconductor laser.
A GaN substrate having a thickness of 80 μm is manufactured by polishing a GaN substrate having a thickness of 00 μm and then removing the sapphire substrate by polishing.

Further, since the edge emitting semiconductor laser shown in FIG. 13 is formed on a GaN substrate, the resonator mirror can be formed by cleavage. as a result,
There was no reflection on the substrate, and the beam shape was unimodal. Also, since the thermal conductivity is higher than that of the sapphire substrate, the heat radiation characteristics are improved, high output operation is possible, and the life is 50%.
Even at 30 ° C. and 30 mW operation, it extends up to 250 hours.

As shown in FIG. 13, Ga on a single crystal substrate
Several methods have been proposed for producing a GaN-based semiconductor substrate by separating a GaN-based semiconductor layer from a substrate after growing an N-based semiconductor thickly. For example, Japanese Patent Application Laid-Open No. Hei 7-202265
JP-A-7-165498 discloses that a buffer layer made of ZnO is formed on a sapphire substrate, a GaN-based semiconductor is grown thereon, and then the buffer layer is dissolved and removed. And a method of making the same separately.

Japanese Patent Application Laid-Open No. Hei 10-229218 discloses that
A first wafer having a GaN-based semiconductor grown on a first substrate and a second wafer having a GaN-based semiconductor grown on a second substrate are prepared, and the first wafer and the second wafer are prepared. And bonding the GaN-based semiconductors so that the GaN-based semiconductors are in close contact with each other, and then polishing and removing the first substrate and the second substrate.

[0019]

As described above, a high-quality GaN-based compound semiconductor on a heterogeneous substrate such as sapphire can be formed by a low-temperature buffer layer technology or a low-defect substrate manufacturing technology by a combination of selective growth and lateral growth. Crystal growth of the GaN-based semiconductor laser was achieved, and the life of the GaN-based semiconductor laser was prolonged during low-power operation near room temperature. Further, a GaN substrate is manufactured, and the use of this substrate is expected to improve the characteristics of a GaN-based semiconductor laser. However,
A large-area, high-quality GaN substrate that can be industrially used has not been realized yet.

In the method of manufacturing a GaN substrate shown in FIG. 13, the difference in the coefficient of thermal expansion between GaN and a sapphire substrate causes
Wafer warpage occurs when growing thick GaN,
It is difficult to remove a sapphire substrate having a diameter of about 2 inches by polishing. That is, it is difficult to manufacture a large-area GaN substrate by the conventional method of polishing and removing the substrate. Also, in the process of polishing the sapphire substrate due to this warp, defects are introduced into the GaN layer, and the crystallinity is deteriorated, and the threshold current density of the semiconductor laser fabricated thereon is increased. Laser characteristics were not always good.

Further, after bonding the first wafer and the second wafer disclosed in Japanese Patent Application Laid-Open No. Hei 10-229218 such that the respective GaN-based semiconductors are in close contact with each other, the first substrate and the second substrate are bonded together. In the method of removing the substrate, the difference in thermal expansion coefficient between the substrate and the GaN-based semiconductor is
When the N is grown to a large thickness, the wafer is warped. Therefore, in the case of a large-area wafer, the GaN-based semiconductors may not completely adhere to each other over the entire surface of the wafer. In addition, cracks may occur in the process of close contact. In addition, since the first substrate and the second substrate are polished and removed, two expensive substrates are used for manufacturing one GaN substrate, resulting in a high cost.

In the technology disclosed in Japanese Patent Application Laid-Open Nos. 7-202265 and 7-165498, that is, a technology for producing a GaN substrate that does not require polishing and removal of the substrate, a buffer layer made of a thin ZnO film is used. It took a very long time to dissolve and remove, and practical application was difficult.

The present invention solves such a problem of the conventional method of manufacturing a GaN-based semiconductor substrate, and realizes a large-area, high-quality GaN-based semiconductor substrate which can be industrially used, a method of manufacturing the same, and a semiconductor light emitting device. It is intended to provide an element.

[0024]

To achieve SUMMARY OF to the above objects, the invention according to claim 1, the first substrate In _r Al _s G
a _(1-rs) N (0 ≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1) forming a single crystal thin film; and In _r Al _s Ga _(1-rs) N
(0 ≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1)
_{n x Al y Ga (1-} xy) N (0 ≦ x ≦ 1,0 ≦ y ≦ 1, x +
y ≦ 1) a step of attaching to a second substrate having substantially the same thermal expansion coefficient as that of the single crystal, and a step of attaching In _r Al _s Ga from the first substrate.
_(1-rs) N (0 ≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1) A step of separating a single crystal thin film, and a step of separating the In _r Al _s Ga _(1-rs) attached to the second substrate. ₎ N (0 ≦ r ≦ 1,0 ≦ s ≦ 1, r
A + s ≦ 1) single-crystal thin _{film, In x Al y Ga (1} -xy) N
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) A step of epitaxially growing a single crystal, and a step of preparing In _x Al _y G from the second substrate.
a _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single crystal separation step, whereby In _x Al _y Ga _(1-xy)
It is characterized in that a single crystal of N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) is manufactured as a semiconductor substrate.

Further, an invention according to claim 2, wherein, in the method for manufacturing a semiconductor substrate according to claim 1, wherein the second substrate is a polycrystalline _{In t Al u Ga (1-} tu) N (0 ≦ t ≦ 1 , 0 ≦ u ≦
1, t + u ≦ 1) substrate.

[0026] The invention of claim 3, wherein, in the method for manufacturing a semiconductor substrate according to claim 2, wherein, In _r Al _s Ga
_{(1-rs) N (0} ≦ r ≦ 1,0 ≦ s ≦ 1, r + s ≦ 1) single-crystalline thin film, polycrystalline _{In t Al u Ga (1-} tu) N (0 ≦ t ≦ 1,
0 ≦ u ≦ 1, t + u ≦ 1) Substrate, In _x Al _y Ga _(1-xy)
N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) is characterized in that all single crystals have the same composition.

According to a fourth aspect of the present invention, the first substrate has In
_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u
≦ 1) a step of forming a single crystal thin film, and
n_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t +
u ≦ 1) a step of separating a single crystal thin film;_tAl_uGa
_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) single connection
For attaching a crystalline thin film to a second substrate via a low melting point metal
And the In pasted on the second substrate_tAl_uGa
_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) single connection
At a temperature equal to or higher than the melting point of the low melting point metal,_xA
l_yGa_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦
1) a step of epitaxially growing a single crystal;
In from plate_xAl_yGa_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) The temperature of the single crystal is higher than the melting point of the low melting point metal.
By the step of separating_xAl_yGa _(1-xy)N (0
≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) Single-crystal semiconductor
It is characterized by being manufactured as a plate.

According to a fifth aspect of the present invention, the first substrate is provided.
In_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1,
t + u ≦ 1) a step of forming a single crystal thin film and a first substrate
To In_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦
1, t + u ≦ 1) a step of separating a single crystal thin film;_tA
l_uGa_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦
1) A single crystal thin film is formed through a molten metal
A step of attaching to the board, and a step of attaching I to the second substrate.
n_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t +
u ≦ 1) Temperature above the melting point of metallic Ga on single crystal thin film
And In_xAl_yGa_{( 1-xy)}N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) A single crystal is epitaxially grown and metal
A step of cooling Ga without coagulating;
In_xAl_yGa_{(1 -xy)}N (0 ≦ x ≦ 1,0 ≦ y ≦ 1, x
+ Y ≦ 1) Separating the single crystal at a temperature higher than the melting point of metallic Ga
In step_xAl_yGa_(1-xy)N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) Single crystal as semiconductor substrate
It is characterized by being manufactured by

Further, an invention according to claim 6, wherein, in the method for manufacturing a semiconductor substrate according to claim 4 or claim 5, wherein the first substrate is _{In t Al u Ga (1-} tu) N (0 ≦ t ≤1,
0 ≦ u ≦ 1, t + u ≦ 1) It is characterized by having a thermal expansion coefficient similar to that of a single crystal thin film.

According to a seventh aspect of the present invention, there is provided a semiconductor device according to the first aspect, wherein the semiconductor substrate is made of In _x Al _y Ga _(1-xy) N ( 0 ≦
x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) It is characterized by being composed of a single crystal.

The invention according to claim 8 provides a semiconductor light emitting device.
The device according to claim 7, wherein_xAl_yGa _(1-xy)N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) on single crystal semiconductor substrate
A general formula In containing at least one PN junction_vAl
_wGa (_1-VW) N (0 ≦ v ≦ 1, 0 ≦ w ≦ 1, v + w ≦ 1)
GaN-based semiconductor multilayer structure represented by
It is characterized by being.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing an example of a manufacturing process of a semiconductor substrate according to the present invention. In the example of the manufacturing process of FIG. The first substrate (single crystalline substrate) 50 In _r Al _s Ga
_(1-rs) N (0 ≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1) forming a single crystal thin film 52 (FIG. 1A); b. _{In r Al s Ga (1-} rs) N (0 ≦ r ≦ 1,0 ≦ s ≦
1, r + s ≦ 1) The single crystal thin film 52 is formed of In _x Al _y Ga
_(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) Step of sticking to a second substrate 53 having substantially the same thermal expansion coefficient as a single crystal (FIG. 1B) And c. From the first substrate (single crystalline substrate) 50 In _r Al _s Ga
_(1-rs) N (0 ≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1) a step of separating the single-crystal thin film 52 (FIG. 1C); d. In _r Al _s Ga attached to the second substrate 53
_(1-rs) N (0 ≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1) In _x Al _y Ga _(1-xy) N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) a step of epitaxially growing the single crystal 54 (FIG. 1D); e. From the second substrate 53, In _x Al _y Ga _(1-xy) N (0 ≦
x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) a step (FIG. 1 (e)) of separating the single crystal 54, and finally In _x Al _y
Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1)
A single crystal substrate 54 is manufactured.

Here, the first substrate (single crystal substrate) 50 is a sapphire (0001) c-plane, a sapphire (11
-20) a-plane, MaAl ₂ O ₄ spinel (111) plane, 6
H-SiC (0001) c-plane, 6H-SiC (1-10
0) An m-plane or the like can be used.

In step a, In _r Al _s Ga
_(1-rs) N (0 ≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1) MOCVD, HV
Although means such as PE and MBE can be used, the present invention is not limited to the above method, and the first substrate (single crystal substrate) 50
_{A, In r Al s Ga (1} -rs) N (0 ≦ r ≦ 1,0 ≦ s ≦
(1, r + s ≦ 1) Other methods may be used as long as the single-crystal thin film 52 can be crystal-grown.
_{Further, In r Al s Ga (1} -rs) N (0 ≦ r ≦ 1,0 ≦ s ≦
1, r + s ≦ 1) When growing the single crystal thin film 52, Ga
The low-temperature buffer layer, such as N or AlN not safely be deposited above the first substrate surface layer (single-crystal substrate) 10 crystal layer grown using the _{In r Al s Ga (1-} rs) N (0 ≦ r ≦
1,0 ≦ s ≦ 1, r + s ≦ 1) Any single crystal may be used.

In the step b, the second substrate 53
A single crystal or polycrystalline molybdenum substrate (6 × 10 ⁻⁶ k ⁻¹ ), a single crystal YAlO ₃ substrate _{, a} single crystal GG
G (Gd ₃ Ga ₅ O ₁₂ ) substrate or a thermal expansion coefficient of I
_{n x Al y Ga (1-} xy) N (0 ≦ x ≦ 1,0 ≦ y ≦ 1, x +
y ≦ 1) A single crystal, a polycrystal, an amorphous body, or the like manufactured by adjusting the raw material composition so as to be approximately the same as the single crystal 54 can be used.

As a method of attaching the wafer to the second substrate 53, the wafer is heated in a nitrogen atmosphere pressurized to a pressure higher than the decomposition pressure of the nitride semiconductor, and In _r Al _s Ga _(1-rs) N ( 0
≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1) Although it is possible to directly bond the single crystal thin film 52 and the second substrate 53 by diffusion bonding, the first substrate 50 in the step c is used. Of In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y
.Ltoreq.1, x + y.ltoreq.1) Any other method may be used as long as it does not hinder the epitaxial growth of the single crystal 54.

The degree of sticking is determined by In _r Al _s Ga
_(1-rs) N (0 ≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1) The entire surface of the single crystal thin film 52 does not need to be completely bonded to the second substrate 53, and Removal of the first substrate 50 in the step and In _x Al _y Ga _(1-xy) N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) As long as it does not hinder the epitaxial growth of the single crystal 54, it may be partially bonded. Further, the bonding strength, an In _x Al in the first step of the removal and d of the substrate 50 in the c step _{y Ga (1-xy) N} (0 ≦ x ≦ 1,0 ≦ y ≦
(1, x + y ≦ 1) If there is no problem in epitaxially growing the single crystal 54, it may be weak.

In the step c, the first substrate (simple substrate)
(Crystal substrate) 50_rAl_sGa_{(1-r -s)}N (0 ≦ r ≦
1,0 ≦ s ≦ 1, r + s ≦ 1) Separated from single crystal thin film 52
Chemical etching, polishing, etc. can be used
, But is not particularly limited and can be used as appropriate
It is.

In the step d, the second substrate 53
In pasted on_rAl_sGa_{(1-r -s)}N (0 ≦ r ≦
1,0 ≦ s ≦ 1, r + s ≦ 1) On the single crystal thin film 52, I
n_xAl_yGa_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x +
y ≦ 1) A method of epitaxially growing the single crystal 54
Although not particularly limited, a thick single crystal layer
HVPE, high-speed MOCVD, etc.
It is desirable to use a method with a high growth rate. In addition, n-type and p-type
Control the conduction type by doping
And it is possible.

In the step e, the second substrate 53
From In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) As a method for separating the single crystal 54,
Chemical etching, polishing and the like can be used, but are not particularly limited and can be appropriately performed.

FIG. 2 is a diagram showing a specific example of the example of the manufacturing process shown in FIG. In the example of the process shown in FIG.
An n-type GaN single crystal substrate is manufactured.

Referring to FIG. 2, first, on a (0001) c-plane sapphire substrate 50 having a diameter of 2 inches, hydrogen gas is used as a carrier gas at 520 ° C., and trimethyl gallium is used as a group III material and ammonium is used as a group V material. And Ga
An N buffer layer 51 is deposited to a thickness of about 25 nm,
The temperature is raised to 0 ° C., and a GaN single crystal layer 52 is grown to 8 μm (FIG. 2A).

Next, the surface of the polycrystalline Mo substrate 53 whose surface has been polished into a mirror surface and the surface of the GaN single crystal 52 are brought into close contact with each other, and are transferred to an annealing apparatus while being strongly fixed by a heat-resistant jig. Then, in a nitrogen atmosphere, 20 atm, 11
Annealing is performed at 00 ° C. to cause diffusion bonding of the two (FIG. 2B).

Next, the sapphire (0001) substrate 50 is polished and removed using a polishing apparatus (FIG. 2C).
At this time, since the GaN buffer layer 51 is a layer including a polycrystalline layer grown at a low temperature, it is polished and removed at the same time, and the exposed surface of the GaN single crystal layer 52 is mirror-polished.

Next, the Mo substrate 53 is transferred to an HVPE apparatus, and N ₂ gas is used as a carrier gas and HC is added to the reaction gas.
l gas, metal gallium for group III raw material, ammonia gas for group V raw material, silicon tetrachloride (SiCl
_{Using 4} ), an n-type GaN single crystal 54 is grown to 300 μm on the surface of the GaN single crystal layer 52 exposed at 1050 ° C. (FIG. 2D).

Next, the Mo substrate 5 is polished using a polishing apparatus.
3 is removed by polishing. Further, the exposed GaN single crystal layer 5
4 is mirror-polished to produce an n-type GaN single crystal substrate 54 having a thickness of 300 μm (FIG. 2E). Thus, an n-type GaN single crystal substrate can be manufactured as a semiconductor substrate.

In the example of the manufacturing process shown in FIGS. 1 and 2, the above-described process eliminates the occurrence of cracks and warpage due to the thick growth on the substrate 50 having a large difference in thermal expansion coefficient.
In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1,
0 ≦ y ≦ 1, x + y ≦ 1) A single crystal substrate 54 is manufactured. The second substrate 53 has a thermal expansion coefficient of an In _x Al _y
Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1)
If it is almost the same as the single crystal 54, the crystal structure and the lattice constant may be different, so that the range of substrate selection is increased, and by selecting an inexpensive substrate, In _x A
_{l y Ga (1-xy)} N (0 ≦ x ≦ 1,0 ≦ y ≦ 1, x + y ≦
1) A single crystal substrate 54 is manufactured.

By the way, in the manufacturing method of FIGS. 1 and 2, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) The second made of a material different from the single crystal 54
When the substrate 53 is used, the crystal growth conditions such as the crystal growth temperature and the growth atmosphere may be restricted depending on the melting point and the chemical stability of the second substrate. Furthermore, constituent elements of the second substrate 53 is _{In x Al y Ga (1-} xy) N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) There is a concern that the impurities may diffuse into the single crystal 54 as impurities.

To avoid such a problem, the second
Substrate 53 of In_xAl_yGa_{(1-x -y)}N (0 ≦ x ≦ 1,
0 ≦ y ≦ 1, x + y ≦ 1) Is the same type of material as the single crystal layer 54?
Polycrystalline In_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1,0
≦ u ≦ 1, t + u ≦ 1) It is preferable to use a substrate. Sand
The second substrate 53 is made of polycrystalline In._tAl_uGa_(1-tu)N
(0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1)
good.

[0050] Figure 3 is polycrystalline and the second substrate 53 In _t Al _u
Ga _(1-tu) N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1)
It is a figure which shows the example of a manufacturing process in the case of making into a board | substrate. In the example of FIG. 3, the semiconductor substrate is n-type In _0.1 Ga _0.9 N
A single crystal substrate is being manufactured.

Referring to FIG. 3, first, on a (0001) c-plane sapphire substrate 50 having a diameter of 2 inches, hydrogen gas is used as a carrier gas at 520 ° C., and trimethylgallium is used as a group III material and ammonium is used as a group V material. And Ga
An N buffer layer 51 is deposited to a thickness of about 25 nm,
The temperature is raised to 0 ° C., and a GaN single crystal layer 52 is grown to 8 μm.
(FIG. 3 (a)).

Next, the surface of the GaN single-crystal layer 52 and the polycrystalline GaN substrate 53, whose surfaces have been polished to a mirror surface, are brought into close contact with each other (FIG. 3B), and are strongly fixed with a heat-resistant jig. Transfer to the annealing device. Then, annealing is performed at 20 atmospheres and 1100 ° C. in a nitrogen atmosphere, and the two are bonded by diffusion.

Next, the sapphire (0001) substrate 50 is polished and removed using a polishing apparatus. At this time, GaN
Since the buffer layer 51 is a layer including a polycrystalline layer grown at a low temperature, it is polished and removed at the same time, and the surface of the exposed GaN single-crystal layer 52 is mirror-polished (FIG. 3).
(c)).

Next, the polycrystalline GaN substrate 53 is
Transferred to E device, the N ₂ gas as a carrier gas, trimethyl gallium III group material, trimethyl indium, V
Using ammonia gas, monomethylhydrazine as the group material and monosilane as the n-type dopant gas, the surface of the GaN single crystal layer 52 exposed at 800 ° C. is n-type In _0.1 Ga _0.9
An N single crystal 54 is grown to a thickness of 200 μm (FIG. 3D).

Next, using a polishing apparatus, polycrystalline Ga
The N substrate 53 is removed by polishing. Further, the exposed surface of the GaN single-crystal layer 54 is polished to a mirror-like surface to a thickness of about 2
An n-type In _0.1 Ga _0.9 N single crystal substrate 54 having a thickness of 00 μm is manufactured (FIG. 3E).

As described above, according to the process example of FIG.
Substrate 53 is polycrystalline In_tAl_uGa _(1-tu)N (0 ≦ t ≦
1,0 ≦ u ≦ 1, t + u ≦ 1) thermal expansion
Crack due to thick growth on substrate with large coefficient difference
Of practical area without generation and warpage of In_xAl_yGa
_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single connection
A crystal substrate 54 is manufactured. In addition, the constituent elements are the same
Therefore, contamination of the substrate with impurities is reduced.

By the way, in the example of the manufacturing process shown in FIG.
In the substrate 53_xAl_yGa_(1-xy)N (0 ≦ x ≦ 1,0 ≦
y ≦ 1, x + y ≦ 1) The same type of material as the single crystal layer 54 is used.
Polycrystalline In_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1,0 ≦ u
≦ 1, t + u ≦ 1) By using a substrate, In_x
Al_yGa_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y
≦ 1) The growth condition of the single crystal layer 54 depends on the second substrate 53
Eliminate restrictions, and constituent elements of substrate 53 are mixed as impurities
Has been reduced, but polycrystalline In_tAl_uGa _(1-tu)
The N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) substrate 53
In_xAl_yGa_{( 1-xy)}N (0 ≦ x ≦ 1,0 ≦ y ≦ 1, x
+ Y ≦ 1) Since the mixed crystal composition is different from that of the single crystal layer,
Second substrate 53 and In_xAl_yGa_(1-xy)N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) The single crystal layer 54
Different expansion coefficients. Therefore, the heat caused by the difference in thermal expansion coefficient
There is a concern that defects may occur due to distortion.

In order to avoid such a problem, FIG.
In the manufacturing process _{example, In r Al s Ga (1} -rs) N (0 ≦
r ≦ 1,0 ≦ s ≦ 1, r + s ≦ 1) single-crystal thin film 52, a polycrystalline _{In t Al u Ga (1-} tu) N (0 ≦ t ≦ 1,0 ≦ u ≦
1, t + u ≦ 1) substrate _{53, In x Al y Ga (} 1-xy) N
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) The composition of the single crystal 54 is made all the same, the difference in the coefficient of thermal expansion between the second substrate 53 and the crystal layer 54 is made almost zero, It is desirable to reduce the occurrence of defects due to

[0059] Figure 4 is _{In r Al s Ga (1-} rs) N (0 ≦ r ≦
1,0 ≦ s ≦ 1, r + s ≦ 1) single-crystal thin film 52, a polycrystalline _{In t Al u Ga (1-} tu) N (0 ≦ t ≦ 1,0 ≦ u ≦ 1, t
+ U ≦ 1) substrate 53, In _x Al _y Ga _(1-xy) N (0 ≦ x
.Ltoreq.1, 0.ltoreq.y.ltoreq.1, x + y.ltoreq.1) This is a diagram showing an example of a manufacturing process when the compositions of the single crystals 54 are all the same. In the example of FIG. 4, n-type Al _0.15 G
a _0.85 N single crystal substrate is manufactured.

Referring to FIG. 4, first, on a (0001) c-plane sapphire substrate 50 having a diameter of 2 inches, hydrogen gas is used as a carrier gas at 520 ° C., and trimethylgallium is used as a group III material and ammonium is used as a group V material. And Al
_{A 0.15} Ga _0.85 N buffer layer 51 is deposited to a thickness of about 25 nm, and then the temperature is raised to 1050 ° C. to grow an Al _0.15 Ga _0.85 N single crystal layer 52 to 8 μm (FIG. 4A).

Next, a polycrystalline Al _0.15 Ga _0.85 N substrate 53 whose surface is polished to a mirror surface and an Al _0.15 Ga
The surface of the _0.85 N single crystal 52 is brought into close contact (FIG. 4B), and is transferred to an annealing apparatus while being strongly fixed with a heat-resistant jig. Then, annealing is performed at 20 atmospheres and 1100 ° C. in a nitrogen atmosphere, and the two are bonded by diffusion.

Next, the sapphire (0001) substrate 50 is polished and removed using a polishing apparatus. At this time, Al
_{Since the 0.15} Ga _0.85 N buffer layer 51 is a layer including a polycrystalline layer grown at a low temperature, it is polished and removed at the same time, and the surface of the exposed Al _0.15 Ga _0.85 N single crystal layer 52 is mirror-polished (FIG. 4). (c)).

Next, an Al _0.15 Ga _0.85 N substrate 53
Transferred to an OVPE apparatus and exposed at 1050 ° C. using H ₂ gas as a carrier gas, trimethylgallium and trimethylaluminum as a group III raw material, ammonia gas as a group V raw material, and monosilane as an n-type dopant gas.
l _0.15 Ga _0.85 N The n-type Al _0.15 G
a _0.85 N single crystal 54 is grown to 300 μm (FIG. 4)
(d)).

Then, using a polishing apparatus, polycrystalline Al
_{The 0.15} Ga _0.85 N substrate 53 is removed by polishing. Further, the exposed surface of the Al _0.15 Ga _0.85 N single crystal layer 54 is polished to a mirror-like surface, and a 300 μm thick n-type Al _0.15 Ga
_{A 0.85} N single crystal substrate 54 is manufactured (FIG. 4E).

In the above example, an n-type A
An example of manufacturing a l _0.15 Ga _0.85 N single crystal substrate has been described.
As another example, an n-type GaN single crystal substrate can be manufactured. A method for manufacturing an n-type GaN single crystal substrate will be described with reference to FIG. 4 for convenience.

When fabricating an n-type GaN single crystal substrate as a semiconductor substrate, first, a (0001) c having a diameter of 2 inches is used.
On a planar sapphire substrate 50, at 520 ° C., hydrogen gas was used as a carrier gas, and trimethylgallium and V
GaN buffer layer 5 using ammonium as group material
1 was deposited to about 25 nm, and then heated to 1050 ° C.
The GaN single crystal layer 52 is grown to 8 μm (FIG. 4A).

Then, the surface of the polycrystalline GaN substrate 33 and the surface of the GaN single crystal 32 are brought into close contact with each other (FIG. 4B), and are transferred to an annealing apparatus while being strongly fixed by a heat-resistant jig. Then, annealing is performed at 20 atmospheres and 1100 ° C. in a nitrogen atmosphere, and the two are bonded by diffusion.

Next, the sapphire (0001) substrate 50 is polished and removed using a polishing apparatus. At this time, GaN
Since the buffer layer 51 is a layer including a polycrystalline layer grown at a low temperature, it is polished and removed at the same time, and the surface of the exposed GaN single crystal layer 52 is mirror-polished (FIG. 4).
(c)).

Next, the polycrystalline GaN substrate 53 is
Using an N ₂ gas as a carrier gas, HCl gas as a reaction gas, metal gallium as a group III material, ammonia gas as a group V material, and silicon tetrachloride (SiCl ₄ ) as an n-type dopant gas, Ga exposed at 1050 ° C.
On the surface of the N single crystal layer 52, 300
It grows by μm (FIG. 4D).

Then, using a polishing apparatus, polycrystalline Ga
The N substrate 53 is removed by polishing. Further, the exposed surface of the GaN single crystal layer 54 is polished to a mirror-like shape to have a thickness of 30%.
A 0 μm n-type GaN single crystal substrate 54 is manufactured.
(e)).

As described above, according to the example of the manufacturing process shown in FIG.
In_rAl_sGa_(1-rs)N (0 ≦ r ≦ 1,0 ≦ s ≦ 1, r
+ S ≦ 1) Single-crystal thin film 52, polycrystalline In_tAl_uGa
_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) substrate
53, In_xAl_yGa_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) The compositions of the single crystals 54 are all the same
Therefore, the difference in the coefficient of thermal expansion is greater than in the manufacturing method of FIG.
Crack generation and warpage are reduced, and the manufacturing method of FIG.
Even higher quality practical area of In_xAl_yGa_(1-x
-y)N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single crystal group
A plate 54 is made. Since the constituent elements are the same,
Impurities from the substrate are also reduced.

In the present invention, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦
y ≦ 1, x + y ≦ 1) A single crystal substrate 54 can be provided. Then, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) In the step of growing the single crystal 54, a conductive substrate exhibiting a desired conductivity type can be provided by doping an n-type or p-type dopant.

That is, in the present invention, a GaN-based semiconductor
Little difference in coefficient of thermal expansion, lattice matching, heat transfer
Large-area In with conductivity, cleavage, and conductivity_xAl_yG
a_{(1 -xy)}N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single
A crystal substrate can be provided. Further, the first substrate 50 is
Fire (0001) c-plane, sapphire (11-20) a
Surface, MgAl_TwoO_FourSpinel (111) plane, 6H-SiC
(0001) c-plane, 6H-SiC (1-100) m-plane, etc.
Can be used, (00) depends on the plane direction of the substrate.
01) In having a c-plane or (1-100) m-plane as a main surface_xA
l_yGa_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦
1) It becomes a single crystal substrate. For example, the first substrate 50
Fire (0001) c-plane, sapphire (11-20) a
Surface, MgAl_TwoO_FourSpinel (111) plane, 6H-SiC
If the (0001) c-plane is used, the (0001) c-plane is mainly used.
Surface In_xAl_yGa_(1-xy)N (0 ≦ x ≦ 1,0 ≦ y
≦ 1, x + y ≦ 1) 6H-SiC
If a (1-100) m-plane substrate is used, (1-100)
In with m-plane as the main surface_xAl_yGa_(1-xy)N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) It becomes a single crystal substrate.

Further, in the present invention, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) on the single crystal substrate 54, the general formula _{In v Al w Ga (1-} VW) N (0 containing at least one P-N junction
≦ v ≦ 1, 0 ≦ w ≦ 1, v + w ≦ 1)
A semiconductor light emitting device can be provided by stacking N-based semiconductor stacked structures.

The semiconductor light emitting device is a semiconductor light emitting device having p
A current is applied to the electrodes corresponding to the type and n-type layers, a current is injected into the PN junction, and light is emitted by recombination of carriers. The GaN-based compound semiconductor laminated structure that constitutes the semiconductor light emitting device has at least one PN junction. If a current is injected into the PN junction and light is emitted by recombination of carriers, a homogenous structure is obtained. A junction, a single hetero junction, a double hetero junction, a quantum well structure, a multiple quantum well structure, or any other structure may be used.

In the present invention, the substrate of the semiconductor light-emitting device is formed of In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1,
x + y ≦ 1) Since the single crystal substrate 54 is used and the substrate can be cleaved, when the semiconductor light emitting element is a semiconductor laser, a laser resonator mirror with cleavage having good parallelism and smoothness should be provided. Can be. Further, by making the substrate to the conductive (i.e., an In _x Al _y Ga
_(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) Doping the single crystal substrate 54 with an n-type or p-type dopant, and light emission with electrodes formed on the back surface of the substrate It can be an element.

FIG. 5 shows a specific example of the semiconductor light emitting device according to the present invention.
It is a figure showing an example. The semiconductor light emitting device shown in FIG.
It is configured as a body laser. Referring to FIG.
The semiconductor light emitting device of the above is manufactured by the manufacturing method described above.
N-Al_0.15Ga_0.85On the N single crystal substrate 54, nG
aN buffer layer 31, n-Al_0.15Ga_0.85N clad
Layer 32, n-GaN light guide layer 33, In_0.15Ga_0.85
N / In_0.02Ga_0.98N multiple quantum well structure active layer 34,
p-GaN optical guide layer 35, p-Al_0.15Ga _0.85N
A lad layer 36 and a p-GaN cap layer 37 are sequentially laminated.
It has a laminated structure.

Then, a portion from the surface of the p-type GaN cap layer 37 of the laminated structure to the middle of the p-Al _0.15 Ga _0.85 N clad layer 36 is etched using the remaining stripe pattern of 5 μm to form a waveguide. A ridge structure is formed. Here, the direction of the waveguide is <1-100>
Direction.

A protective layer 38 made of SiO ₂ is deposited on the surface of the p-Al _0.15 Ga _0.85 N clad layer 36 exposed by forming the ridge structure as described above. A p-side ohmic electrode 39 is formed on the p-GaN cap layer 37. Also, n-Al _0.15
On the back surface of the Ga _0.85 N single crystal substrate 54, an n-side ohmic electrode 40 is formed. The optical resonator surface of this semiconductor laser is formed by cleaving the (1-100) m plane.

In the semiconductor light emitting device shown in FIG.
N buffer layer 31, n-Al _0.15 Ga _0.85 N cladding layer 32, n-GaN optical guide layer 33, In _0.15 Ga _0.85 N
/ In _0.02 Ga _0.98 N multiple quantum well structure active layer 34, p
-GaN optical guide layer _{35, p-Al 0.15 Ga 0.85} N cladding layer 36, p-GaN cap layer 37 was grown by the MOCVD method.

Further, the p-side ohmic electrode 39 is Au /
Pt / Ni was formed by vacuum deposition and heat-treated at a temperature of 700 ° C. for 20 minutes. Also, the n-side ohmic electrode 40
Was formed by vacuum deposition of Al / Ti and heat treatment.

In the semiconductor laser shown in FIG. 5, when a current is applied to the p-side ohmic electrode 39 and the n-side ohmic electrode 40, a current flows in the In _0.15 Ga _0.85 N / In _0.02 Ga _0.98 N multiple quantum well structure active layer. The light is injected, emits light by recombination of carriers, and is reflected and amplified by the resonator surface formed by cleavage, and is output to the outside as laser light.

In the semiconductor laser of FIG. 5, an n-Al _0.15 Ga _0.85 N single crystal substrate having the same composition as that of the cladding layer is used for the substrate 54, so that the cladding layer is smaller than when a sapphire or GaN substrate is used. Even when the mixed crystal ratio of Al is increased, cracks are unlikely to occur during crystal growth, so that a cladding layer having a composition and a thickness sufficient for confining light can be formed. As a result, a semiconductor laser having a low oscillation threshold current density without deterioration of the beam shape due to light leakage from the cladding layer is manufactured.

FIG. 6 is a view showing another example of the manufacturing process of the semiconductor substrate according to the present invention. In the example of the manufacturing process shown in FIG. The first substrate (single crystal substrate) 10 In _t Al _u Ga
_(1-tu) a step of forming an N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) single crystal thin film 12 (FIG. 6A); b. From the first substrate (single crystal substrate) 10 In _t Al _u Ga
_(1-tu) a step of separating the N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) single crystal thin film 12 (FIG. 6B); c. _{In t Al u Ga (1-} tu) N (0 ≦ t ≦ 1,0 ≦ u ≦
1, t + u ≦ 1) a step of attaching the single crystal thin film 12 to the second substrate 15 via the low melting point metal 16 (FIG. 6C)
And d. In _t Al _u Ga affixed to the second substrate 15
_(1-tu) N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) on the single crystal thin film 12 at a temperature equal to or higher than the melting point of the low melting metal 16,
_{In x Al y Ga (1-} xy) N (0 ≦ x ≦ 1,0 ≦ y ≦ 1, x
+ Y ≦ 1) a step of epitaxially growing the single crystal 17 (FIG. 6D); e. From the second substrate 15, In _x Al _y Ga _(1-xy) N (0 ≦
x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) a step of separating the single crystal 17 at a temperature equal to or higher than the melting point of the low melting point metal 16 (FIG. 6)
(E)), and finally In _x Al _y Ga _(1-xy)
N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single crystal substrate 1
7 are produced.

Here, the first substrate (single crystal substrate) 10 is a sapphire (0001) c-plane, a sapphire (11
-20) a-plane, MaAl ₂ O ₄ spinel (111) plane, 6
H-SiC (0001) c-plane, 6H-SiC (1-10
0) An m-plane or the like can be used.

[0086] In the step of a, In _t Al _u Ga
_(1-tu) N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) MOCVD, HV
Although PE, MBE and the like can be used, the present invention is not limited to the above method, and the first substrate (single crystal substrate) 10
n _t Al _u Ga _(1-tu) N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t +
u ≦ 1) Other methods may be used as long as the single-crystal thin film 12 can be crystal-grown. Also, I
n _t Al _u Ga _(1-tu) N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t +
u ≦ 1) Before growing the single crystal thin film 12, GaN or Al
No harm in a low-temperature buffer layer or other layers deposited above such as N, the first substrate (single crystalline substrate) 10 crystal layer surface layer grown using the In _t Al _u Ga _{(1- tu)} N (0 ≦
t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) Any single crystal may be used.

In step b, the first substrate (single substrate)
(Crystal substrate) 10 to In_tAl_uGa_{(1 -tu)}N (0 ≦ t ≦
1,0 ≦ u ≦ 1, t + u ≦ 1) Separating the single crystal thin film 12
As a method, In_tAl_uGa_(1-tu)N (0 ≦ t ≦
1,0 ≦ u ≦ 1, t + u ≦ 1) Supporting single crystal thin film 12
After affixing to the board, use chemical etching, polishing, etc.
A method of removing one substrate (single crystal substrate) 10 or a first substrate
Plate (single crystal substrate) 10 and In _tAl_uGa_(1-tu)N (0 ≦ t
≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) between the single crystal layer 12
After growing a layer that can be etched etc.,
Etch and lift off the first substrate (single crystal substrate
Plate) 10 can be used.
As for the method, it is not particularly limited to the above method.
Absent.

In the step c, the low melting metal 16
Has a melting point of In _x Al _y Ga _(1-xy) N (0 ≦ x
A single metal or an alloy may be used as long as it is lower than the growth temperature of ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) and the temperature at which the second substrate 15 is separated. For example, indium, tin, gallium and the like can be used. Further, as the second substrate 15, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1,
0 ≦ y ≦ 1, x + y ≦ 1) When a single crystal is epitaxially grown, it is sufficient that the single crystal is stable at the growth temperature and in the growth atmosphere, and sapphire, Si, quartz or the like may be used as a single crystal, polycrystal, or amorphous. And can be used.

In the step d, the second substrate 15
In pasted on_tAl_uGa_{(1 -tu)}N (0 ≦ t ≦
1,0 ≦ u ≦ 1, t + u ≦ 1) Low on the single crystal thin film 12
At a temperature equal to or higher than the melting point of the melting point metal 16, In_xAl_yGa
_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single connection
When the crystal 17 is epitaxially grown, In_tAl_uGa
_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) single connection
Since the crystalline thin film 12 is on the molten metal 16, the second substrate
15 and In_xAl_yGa_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) Difference in thermal expansion coefficient from single crystal 17 or crystal structure
The crystal growth of the single crystal 17 is not affected by the difference in structure, etc.
move on. The method of crystal growth is not particularly limited.
However, since the thick single crystal layer 17 is grown, the HVPE method is used.
A method with a high growth rate such as a high-speed MOCVD method is desirable.
No. Also, doping with n-type or p-type dopants
It is possible to control the conduction type.

FIGS. 7 and 8 show a specific example of the example of the manufacturing process shown in FIG. 7 and 8, an n-type GaN single crystal substrate is manufactured as a semiconductor substrate.

Referring to FIGS. 7 and 8, first, an MO is placed on a (0001) c-plane sapphire substrate 10 having a diameter of 2 inches.
The GaN layer 12 is grown by the CVD method. The GaN layer 12 is grown by MOCVD at 520 ° C. using hydrogen gas as a carrier gas and trimethylgallium as a group III raw material.
GaN buffer layer 1 using ammonia as group V material
1 was deposited to about 25 nm, and then heated to 1050 ° C.
This is performed by growing the GaN single crystal layer 12 by 10 μm (FIG. 7A).

Next, the support substrate 1 was coated with an organic adhesive 13.
4 is bonded to the surface of the GaN single crystal layer 12 (FIG. 7 (b-
1)) Then, the sapphire substrate 10 is polished and removed by a polishing apparatus (FIG. 7B-2).

Next, the quartz substrate 15 and the GaN single crystal layer 1
2 are bonded with indium 16 (FIG. 7C-1).
Here, as a bonding method, indium 16 is placed on a quartz substrate 15, and a GaN single crystal layer 12 attached to a support substrate 14 is further placed on the quartz substrate 15 with the surface of the GaN single crystal layer 12 facing indium 16. The indium 16 is heated to a temperature equal to or higher than the melting point of 16 to bond the indium 16 in a molten state.

Thereafter, the organic adhesive 13 with an organic solvent is used.
Is dissolved to separate the support substrate 14 (FIG. 8C-
2)).

Next, the quartz substrate 15 to which the GaN single crystal layer 12 was bonded was transferred to an HVPE apparatus, N ₂ gas was used as a carrier gas, HCl gas was used as a reaction gas, metal gallium was used as a group III raw material, and metal gallium was used as a group V raw material. Using silicon tetrachloride (SiCl ₄ ) for ammonia gas and n-type dopant gas,
At 1050 ° C., an n-type GaN single crystal 17 is grown to a thickness of 300 μm on the surface of the GaN single crystal layer 12 (FIG. 8).
(D)).

Next, the quartz substrate 15 on which the n-type GaN single crystal layer 17 has been grown is heated to a temperature equal to or higher than the melting point of the indium 16, and the indium 16 is melted to separate the quartz substrate 15 (FIG. 8 (e-1)). )). Thereafter, using a polishing apparatus, the GaN buffer layer 11 is polished and removed.
The surface of the GaN single crystal layer 17 is mirror-polished,
An n-type GaN single crystal substrate 17 having a thickness of about 300 μm is manufactured (FIG. 8E-2). Thus, an n-type GaN single crystal substrate can be manufactured as a semiconductor substrate.

In the example of the manufacturing process shown in FIGS.
_xAl_yGa_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y
≦ 1) In the cooling process after the crystal growth of the single crystal 17,
Until the solidification point of genus 16, In_xAl_yGa_(1-xy)N (0 ≦
x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) The single crystal layer 17 is a substrate
15 because it is not bonded to_xAl_yGa_(1-xy)N
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1)
Even for large areas, low melting point metals 1
Substrate 15 and In during cooling to the freezing point _xAl_y
Ga_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1)
Crack generation and warpage due to thermal shrinkage difference with single crystal layer 17
Is reduced. Therefore, large cracks and warpage are reduced.
Area In_xAl_yGa_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) The single crystal substrate 17 can be manufactured.
You.

The In _x Al _y G from the second substrate 15
a _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) The single crystal layer 17 can be easily separated without damaging the second substrate 15 and reused. Is possible, so that the cost can be reduced. Further, since a single crystal, polycrystal, amorphous, or the like can be used for the second substrate 15, the range of substrate selection is widened, and the cost can be reduced by selecting an inexpensive substrate.

The above-mentioned step c (FIG. 6 (c))
In this case, Ga (gallium) having a melting point near room temperature (about 30 ° C.) is used as the low melting point metal 16, and the steps d and e are performed (FIG. 6).
(D), (e)) In _x Al _y Ga _(1-xy) N (0
≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) From the epitaxial growth of the single crystal 17 to the separation of the second substrate 15, Ga
Can be performed without coagulation.

That is, in this case, a. _Int Al _u Ga _(1-tu) N is provided on the first single crystal substrate 10.
(0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) Single-crystal thin film 12
(FIG. 6A); b. _Int Al _u Ga _(1-tu) from the first single crystal substrate 10
N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) single crystal thin film 1
2 (FIG. 6 (b)); c. _{In t Al u Ga (1-} tu) N (0 ≦ t ≦ 1,0 ≦ u ≦
1, t + u ≦ 1) The single crystal thin film 12 is melted into metallic Ga
(G) the step of attaching to the second substrate 15 via the (gallium) 16 (FIG. 6C); d. In _t Al _u Ga affixed to the second substrate 15
_{On the (1-tu)} N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) single crystal thin film 12, In _x Al _y Ga _{(1 -xy)} N (0 ≦ x ≦ 1,0 ≦
y ≦ 1, x + y ≦ 1) a step of epitaxially growing the single crystal 17 and cooling without solidifying the metal Ga (gallium) 16 (FIG. 6D); e. From the second substrate 15, In _x Al _y Ga _(1-xy) N (0 ≦
x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) The single crystal 17 is
and a a step of separating at a temperature above the melting point of (gallium) 16 (FIG. 6 (e)), and finally, In _x Al _y Ga
_{A (1-xy)} N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single crystal substrate 17 is manufactured.

As described above, in the step c (FIG. 6C),
Ga having a melting point near room temperature (about 30 ° C.) is used as the low melting point metal 16, and In _x Al _y Ga _(1-xy) N ( ₎ is used in the steps d and e (FIGS. 6D and _6E). 0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) By performing the steps from the epitaxial growth of the single crystal 17 to the separation of the second substrate 15 without solidifying Ga, the second substrate 15 and In _x
Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y
.Ltoreq.1) A single crystal substrate can be manufactured without any influence of thermal strain in a cooling process after crystal growth due to a difference in thermal expansion coefficient of the single crystal 17.

Near room temperature (about 30 ° C.) as low melting point metal 16
Using Ga having a melting point for In _x Al _y Ga _(1-xy) N
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) From the epitaxial growth of the single crystal 17 to the separation of the second substrate 15, G
A specific example in the case where a is performed without coagulation will be described. In this specific example, the semiconductor substrate is n
A GaN single crystal substrate is manufactured.

In this specific example, first, a 2 inch diameter
A GaN layer 12 is grown on a (0001) c-plane sapphire substrate 10 by MOCVD. MOC growth of GaN layer 12
The GaN buffer layer 11 is formed to a thickness of about 25 nm at 520 ° C. using hydrogen gas as a carrier gas, trimethylgallium as a group III material and ammonia as a group V material.
The GaN single crystal layer 12 is deposited and then heated to 1050 ° C. to grow the GaN single crystal layer 12 by 10 μm (FIG. 7).
(A)).

Next, the support substrate 1 was coated with an organic adhesive 13.
4 is bonded to the surface of the GaN single crystal layer 12 (FIG. 7 (b-
1)) Then, the sapphire substrate 10 is polished and removed by a polishing apparatus (FIG. 7B-2).

Next, the quartz substrate 15 and the GaN single crystal layer 1
2 are bonded with Ga (gallium) 16 (FIG. 7 (c-
1)). Here, as a bonding method, Ga (gallium) 16 is placed on a quartz substrate 15, and the supporting substrate 1 is further placed thereon.
4 is applied to the GaN single crystal layer 1
2 The surface was placed with the Ga (gallium) 16 side, and heated to a temperature higher than the melting point of Ga (gallium) 16,
16 is melted and bonded.

Thereafter, the organic adhesive 13 with an organic solvent is used.
Is dissolved to separate the support substrate 14 (FIG. 8C-
2)). The temperature at this time is lower than the melting point of Ga (gallium) 16.

Next, the quartz substrate 15 to which the GaN single crystal layer 12 was bonded was transferred to an HVPE apparatus, and N ₂ gas was used as a carrier gas, HCl gas was used as a reaction gas, metal gallium was used as a group III raw material, and metal gallium was used as a group V raw material. Using silicon tetrachloride (SiCl ₄ ) for ammonia gas and n-type dopant gas,
At 1050 ° C., n-type GaN
A single crystal 17 is grown to a thickness of 300 μm (FIG. 8)
(D)).

Next, after growing the n-type GaN single crystal 17,
The quartz substrate 15 is separated by cooling to 35 ° C. which is equal to or higher than the melting point of Ga (gallium) 16 and maintaining this temperature (see FIG.
1)). Thereafter, the GaN buffer layer 11 is polished and removed using a polishing apparatus, and the surface of the GaN single crystal layer 17 is polished to a mirror-like surface.
A GaN single crystal substrate 17 is manufactured (FIG. 8 (e-
2)). Thus, n-type Ga is used as the semiconductor substrate.
An N single crystal substrate can be manufactured.

As described above, the above-mentioned step c (FIG. 6)
(C)), as the low melting point metal 16, around room temperature (about 30 ° C.)
The steps d and e (FIG. 6)
(D), (e)) In _x Al _y Ga _(1-xy) N (0
≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) From the epitaxial growth of the single crystal 17 to the separation of the second substrate 15, Ga
Can be performed without coagulation. In this case, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) Even during the crystal growth of the single crystal 17 and during the cooling process after the growth, the metal Ga (gallium) 16 is in a molten state, so that In _x Al _y Ga _(1-xy) N (0 ≦ x ≤
1,0 ≦ y ≦ 1, x + y ≦ 1) The single crystal layer 17 is not bonded to the second substrate 15. Therefore, In _x Al _y Ga
_{The (1-xy)} N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single crystal layer 17 has the second crystal structure both during crystal growth and during cooling after the growth is completed.
Substrate 15 and In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1,0
.Ltoreq.y.ltoreq.1, x + y.ltoreq.1) Since there is no influence of thermal distortion due to a difference in thermal expansion coefficient from the single crystal layer 17, In _x A
_{l y Ga (1-xy)} N (0 ≦ x ≦ 1,0 ≦ y ≦ 1, x + y ≦
1) Even if the single crystal layer 17 has a large area, there is no crack generation or warpage. Therefore, large area In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) A single crystal substrate 17 can be manufactured.

Since the second substrate 15 can be made of single crystal, polycrystal, amorphous, or the like, the range of substrate selection can be widened and an inexpensive substrate can be selected. Furthermore, the second
In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1,
0 ≦ y ≦ 1, x + y ≦ 1) The single crystal layer 17 is
5 can be easily separated without damaging the substrate 5, so that the substrate can be reused. Therefore, cost reduction is achieved. Further, since the same Ga as the base material element is used as the low melting point metal, impurity contamination by the low melting point metal is reduced.

Further, in the above-described example of the manufacturing process, the first
Substrate (single crystal substrate) _{10, In t Al u Ga (1} -tu) N
(0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) Single-crystal thin film 12
It is preferable to have the same thermal expansion coefficient as that of.

That is, the first substrate (single crystal substrate) 10
Indicates that In _t Al _u Ga _(1-tu) N (0
≦ t ≦ 1,0 ≦ u ≦ 1 , t + u ≦ 1) single-crystal thin film 12 and the thermal expansion coefficient is the same _{degree, In t Al u Ga (1} -tu) N
(0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) Single-crystal thin film 12
May be any as long as the crystal grows. For example, in the case of GaN, GaAs or GGG (Gd ₃ Ga ₅ O ₁₂ ) can be used. In the case of GaAs, cubic GaN grows by using (100) GaAs, and (111) GaAs is grown.
By using s, hexagonal GaN can be grown.

As described above, the first substrate (single crystal substrate) 10
Is In_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦
1, t + u ≦ 1) Thermal expansion coefficient similar to that of single crystal thin film 12
Has thermal expansion with the first substrate 10
In by coefficient difference_tAl_uGa_{(1 -tu)}N (0 ≦ t ≦ 1,0
≦ u ≦ 1, t + u ≦ 1) Cooling after growth of single crystal thin film 12
Warpage and cracks that occur sometimes are reduced. This
Relatively large In_tAl_uGa_(1-tu)N
(0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1)
Can grow. Therefore, In_tAl_uGa
_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) single connection
The work of separating the crystal layer 12 from the first substrate 10 is also a thin crystal.
Easier and better yield than separating layers
I do.

Further, since the difference in thermal expansion coefficient from the first substrate 10 is small, defects caused by thermal distortion are reduced as compared with the case where a substrate having a large difference in thermal expansion coefficient is used.
In _x Al _y Ga _(1-xy) N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) single crystal layer 17 is less the defect _{In t Al u Ga (1-} tu) N (0 ≦ t ≦ 1,0 ≦
u ≦ 1, t + u ≦ 1) Since it grows on the single crystal layer 12,
High quality with few defects. Therefore, in addition to having a small amount of impurities, cracks and warpage are reduced, a large-area, low-cost, high-quality In _x Al _y Ga
_(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single crystal substrate can be manufactured.

The first substrate (single crystal substrate) 10
n _t Al _u Ga _(1-tu) N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t +
u ≦ 1) If the thermal expansion coefficient of the single crystal thin film 12 is substantially the same as that of the single crystal thin film 12, a laminated structure may be provided thereon. For example, as described later, GaAs is used as the first substrate 10.
AlAs or GaAs may be stacked on the substrate.

[0116] _{Also, In t Al u Ga (1} -tu) N (0 ≦ t ≦
1, 0 ≦ u ≦ 1, t + u ≦ 1) As a method for growing the single crystal thin film 12, means such as MOCVD, HVPE, MBE, etc. can be used, but this is not particularly limited and the first method can be used. substrate (single crystal substrate) 10, in _t Al _u Ga
_(1-tu) N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) Other methods may be used as long as the single crystal thin film 12 can be crystal-grown.

[0117] _{Also, In t Al u Ga (1} -tu) N (0 ≦ t ≦
1,0 ≦ u ≦ 1, t + u ≦ 1) Before growing the single-crystal thin film 12, a low-temperature buffer layer such as GaN or AlN or another layer may be deposited first, and the first substrate (single-layer) may be used. crystal substrate) surface layer of the crystal layer grown using 10 an in _t a
_{l u Ga (1-tu)} N (0 ≦ t ≦ 1,0 ≦ u ≦ 1, t + u ≦
1) A single crystal may be used.

FIGS. 9 and 10 are views showing another specific example of the example of the manufacturing process shown in FIG. 9 and 10, an n-type GaN single crystal substrate is manufactured as a semiconductor substrate.

Referring to FIGS. 9 and 10, first, the diameter 2
An AlAs layer 21 and a GaAs layer 22 are sequentially epitaxially grown on an inch (111) GaAs substrate 20 by MOCVD, and this is used as a first substrate 10. Then, a GaN layer 12 is grown on the first substrate 10. The GaN layer 12 is grown by MOCVD, and a GaN buffer layer 11 is deposited at about 520 nm at 520 ° C. using hydrogen gas as a carrier gas, trimethylgallium as a group III material, and ammonia and monomethylhydrazine as a group V material. Then, the temperature is raised to 750 ° C., and the GaN single crystal layer 11 is grown by 20 μm (FIG. 9).
(A)).

Next, the support substrate 1 was coated with an organic adhesive 13.
4 was bonded to the surface of the GaN single crystal layer 12 (FIG. 9 (b-
1)) Then, the AlAs layer 21 is immersed in a hydrofluoric acid aqueous solution.
Is selectively removed by etching to separate the GaAs substrate 20 (FIG. 9B-2).

Next, the quartz substrate 15 and the GaN single crystal layer 1
2 are bonded with Ga (gallium) 16 (FIG. 9 (c-
1)). As a bonding method, Ga (gallium) 16 is placed on a quartz substrate 15, and the GaN single crystal layer 12 bonded to the support substrate 14 is further bonded to the GaAs layer 22 by Ga.
It is placed on the (gallium) 16 side, and heated to a temperature equal to or higher than the melting point of Ga (gallium) 16 to bond the gallium 16 in a molten state.

Thereafter, the organic adhesive 13 with an organic solvent is used.
Is dissolved to separate the support substrate 14 (FIG. 10 (c-
2)). The temperature at this time is lower than the melting point of Ga (gallium) 16.

Next, the quartz substrate 15 to which the GaN single crystal layer 12 was adhered was transferred to an HVPE apparatus, N ₂ gas was used as a carrier gas, HCl gas was used as a reaction gas, metal gallium was used as a group III raw material, and metal gallium was used as a group V raw material. Using silicon tetrachloride (SiCl ₄ ) for ammonia gas and n-type dopant gas,
At 1050 ° C., an n-type GaN single crystal 17 is grown to 300 μm on the surface of the GaN single crystal layer 12 (FIG. 10D).

As described above, after the n-type GaN single crystal 17 is grown, it is cooled to 35 ° C., which is higher than the melting point of Ga (gallium) 16, and the quartz substrate 15 is separated while maintaining this temperature (FIG. 1).
0 (e-1)). Then, using a polishing apparatus, Ga
The As layer 22 and the GaN buffer layer 11 are polished and removed, and the surface of the GaN single crystal layer 17 is mirror-polished to produce an n-type GaN single crystal substrate 17 having a thickness of about 300 μm (FIG. 10E- 2)). Thus, an n-type GaN single crystal substrate can be manufactured as a semiconductor substrate.

In the example of the manufacturing process shown in FIGS. 9 and 10, a (111) GaAs substrate 20 is
Since the layer 21 and the GaAs layer 22 are sequentially laminated and the selectivity of etching between AlAs and GaAs by hydrofluoric acid is very large, the AlAs layer 21 is easily formed.
It is possible to remove only by etching. Therefore,
A large-area GaN single crystal layer 12 can be easily formed using GaAs.
The substrate 20 can be separated without damage. Therefore, a large-area, low-cost GaN substrate can be manufactured.

In the present invention, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦
y ≦ 1, x + y ≦ 1) A single crystal substrate 17 can be provided. Then, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) In the step of growing the single crystal 17, a conductive substrate having a desired conductivity type can be provided by doping with an n-type or p-type dopant.

That is, in the present invention, a GaN-based semiconductor
Little difference in coefficient of thermal expansion, lattice matching, heat transfer
Large-area In with conductivity, cleavage, and conductivity_xAl_yG
a_{(1 -xy)}N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single
A crystal substrate can be provided.

Further, according to the present invention, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) on the single crystal substrate 17, the general formula _{In v Al w Ga (1-} VW) N (0 containing at least one P-N junction
≦ v ≦ 1, 0 ≦ w ≦ 1, v + w ≦ 1)
A semiconductor light emitting device can be provided by stacking N-based semiconductor stacked structures.

The semiconductor light emitting device is a semiconductor light emitting device having p
A current is applied to the electrodes corresponding to the type and n-type layers, a current is injected into the PN junction, and light is emitted by recombination of carriers. The GaN-based compound semiconductor laminated structure that constitutes the semiconductor light emitting device has at least one PN junction. If a current is injected into the PN junction and light is emitted by recombination of carriers, a homogenous structure is obtained. A junction, a single hetero junction, a double hetero junction, a quantum well structure, a multiple quantum well structure, or any other structure may be used.

Further, in the present invention, the substrate of the semiconductor light emitting device has In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1,
x + y ≦ 1) Since the single crystal substrate 17 is used and the substrate can be cleaved, when the semiconductor light emitting element is a semiconductor laser, a laser resonator mirror with cleavage having good parallelism and smoothness should be provided. Can be. Further, by making the substrate to the conductive (i.e., an In _x Al _y Ga
_(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) By doping the single crystal substrate 17 with an n-type or p-type dopant, and emitting light with electrodes formed on the back surface of the substrate It can be an element.

FIG. 11 is a view showing a specific example of the semiconductor light emitting device according to the present invention. Note that the semiconductor light emitting device of FIG. 11 is configured as a semiconductor laser. Referring to FIG. 11, this semiconductor light emitting device has an n-GaN buffer layer 31, an n-Al _0.15 Ga _0.85 N cladding layer 3 on an n-GaN single crystal substrate 17 manufactured by the above-described manufacturing method.
2, n-GaN optical guide layer 33, In _0.15 Ga _0.85 N /
In _0.02 Ga _0.98 N multiple quantum well structure active layer 34, p-
It has a laminated structure in which a GaN light guide layer 35, a p-Al _0.15 Ga _0.85 N clad layer 36, and a p-GaN cap layer 37 are sequentially laminated.

Then, from the surface of the p-type GaN cap layer 37 having the laminated structure to the middle of the p-Al _0.15 Ga _0.85 N clad layer 36, the waveguide is etched by using the remaining 5 μm wide striper pattern. A ridge structure is formed. Here, the direction of the waveguide is <1-10
0> direction.

A protective layer 38 made of SiO ₂ is deposited on the surface of the p-Al _0.15 Ga _0.85 N clad layer 36 exposed by the formation of the ridge structure. A p-side ohmic electrode 39 is formed on the p-GaN cap layer 37. An n-side ohmic electrode 40 is formed on the back surface of the n-GaN single crystal substrate 17. The optical resonator surface of this semiconductor laser is (1-
100) The surface is formed by cleavage.

In the semiconductor light emitting device shown in FIG.
aN buffer layer 31, n-Al _0.15 Ga _0.85 N cladding layer 32, n-GaN optical guide layer 33, In _0.15 Ga _0.85
N / In _0.02 Ga _0.98 N multiple quantum well structure active layer 34,
The p-GaN optical guide layer 35, the p-Al _0.15 Ga _0.85 N cladding layer 36, and the p-GaN cap layer 37 are composed of MOCV
The crystal was grown by Method D.

The p-side ohmic electrode 39 has an Au /
Pt / Ni was formed by vacuum deposition and heat-treated at a temperature of 700 ° C. for 20 minutes. Also, the n-side ohmic electrode 40
Was formed by vacuum deposition of Al / Ti and heat treatment.

In the semiconductor laser shown in FIG. 11, when a current is applied to the p-side ohmic electrode 39 and the n-side ohmic electrode 40, a current flows in the In _0.15 Ga _0.85 N / In _0.02 Ga _0.98 N multiple quantum well structure active layer. The light is injected, emits light by recombination of carriers, and is reflected and amplified by the resonator surface formed by cleavage, and is output to the outside as laser light.

As described above, according to the present invention, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦
y ≦ 1, x + on the y ≦ 1) single crystal substrate 17, the formula includes at least one P-N junction _{In v Al w Ga (1-} VW)
Since a semiconductor light emitting device is formed by stacking GaN-based semiconductor laminated structures represented by N (0 ≦ v ≦ 1, 0 ≦ w ≦ 1, v + w ≦ 1), lattice mismatch and difference in thermal expansion coefficient A light-emitting element comprising a high-quality crystal layer in which the generation of defects due to GaN is suppressed can be provided. It is also possible to manufacture a semiconductor laser having a light emitting element in which an electrode is formed on the back surface of the substrate or a resonator mirror formed by cleavage.

[0138]

As described above, according to the present invention, according to the first aspect of the invention, the first substrate _{In r Al s Ga (1-} rs) N
(0 ≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1) a step of forming a single crystal thin film, and In _r Al _s Ga _(1-rs) N (0 ≦ r ≦ 1,
0 ≦ s ≦ 1, r + s ≦ 1) The single crystal thin film is formed of In _x Al _y Ga
_(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) a step of attaching to a second substrate having a thermal expansion coefficient substantially equal to that of a single crystal; _r Al _s Ga _(1-rs) N (0
≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1) a step of separating a single-crystal thin film, and In _r Al _S G attached to the second substrate.
a _(1-rs) N (0 ≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1) In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1,
0 ≦ y ≦ 1, x + y ≦ 1) a step of epitaxially growing a single crystal, and a step of preparing In _x Al _y Ga _(1-xy) N from the second substrate.
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) By separating the single crystal, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) Since a single crystal is manufactured as a semiconductor substrate, there is no cracking or warpage due to thick growth on a substrate having a large difference in coefficient of thermal expansion, and a practical area of In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) A single crystal substrate can be manufactured. Also, the second
Has a thermal expansion coefficient of In _x Al _y Ga _(1-xy) N (0 ≦
x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) Since it is almost equivalent to a single crystal, its crystal structure and lattice constant may be different, thereby increasing the range of substrate selection and inexpensive substrates. By selecting, low cost In _x Al _y Ga _(1-xy)
A single crystal substrate of N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) can be manufactured.

[0139] According to the second aspect of the present invention, in the method for manufacturing a semiconductor substrate according to claim 1, wherein the second substrate is a polycrystalline _{In t Al u Ga (1-} tu) N (0 ≦ t ≤1,0≤
u ≦ 1, t + u ≦ 1) Since there is no crack or warpage due to thick growth on a substrate having a large difference in thermal expansion coefficient, In _x Al _y Ga _(1-xy) N has a practical area.
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) A single crystal substrate can be manufactured. Further, since the constituent elements are the same, the intrusion of impurities from the substrate can be reduced.

According to the third aspect of the present invention, there is provided a method of manufacturing a semiconductor substrate according to the second aspect, wherein the In _r Al _s
Ga _(1-rs) N (0 ≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1)
Single crystal thin film, polycrystalline _{In t Al u Ga (1-} tu) N (0 ≦ t ≦
1,0 ≦ u ≦ 1, t + u ≦ 1) Substrate, In _x Al _y Ga
_(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) Since the compositions of the single crystals are all the same, the occurrence of cracks and warpage due to the difference in thermal expansion coefficient are further reduced, higher quality practical area of _{in x Al y Ga (1-} xy) N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) A single crystal substrate can be manufactured. Since the constituent elements are the same, impurities from the substrate are also reduced.

According to the fourth aspect of the present invention, the first substrate
In_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1,
t + u ≦ 1) a step of forming a single crystal thin film and a first substrate
To In_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦
1, t + u ≦ 1) a step of separating a single crystal thin film;_tA
l_uGa_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦
1) A single crystal thin film is attached to a second substrate via a low melting point metal.
Attaching step and In attached to the second substrate._tAl_u
Ga_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1)
At a temperature higher than the melting point of the low melting point metal,
_xAl_yGa_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y
≦ 1) a step of epitaxially growing a single crystal;
In from substrate_xAl_yGa_(1-xy)N (0 ≦ x ≦ 1,0 ≦ y
≦ 1, x + y ≦ 1) A single crystal is heated to a temperature not lower than the melting point of
By the process of separating_xAl _yGa_(1-xy)N
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) Single crystal semiconductor
Cracks and warpage are reduced because it is manufactured as a substrate
Practical area of In_xAl_yGa_{(1 -xy)}N (0 ≦ x ≦ 1,
0 ≦ y ≦ 1, x + y ≦ 1) Low cost production of single crystal substrate
can do.

According to the fifth aspect of the present invention, the first
In substrate_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1,0 ≦ u
≦ 1, t + u ≦ 1) a step of forming a single crystal thin film;
From the substrate of_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1,0 ≦
u ≦ 1, t + u ≦ 1) a step of separating a single crystal thin film;
n_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t +
u ≦ 1) The single crystal thin film is
Attaching to the second substrate, and attaching to the second substrate
In_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1,
t + u ≦ 1) Temperature above the melting point of metallic Ga on the single crystal thin film
In degrees_xAl _yGa_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) A single crystal is epitaxially grown and metal
A step of cooling Ga without coagulating;
In_xAl_yGa_(1-xy)N (0 ≦ x ≦ 1,0 ≦ y ≦ 1, x
+ Y ≦ 1) Separating the single crystal at a temperature higher than the melting point of metallic Ga
In step_xAl_yGa_(1-xy)N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) Single crystal as semiconductor substrate
Since it is manufactured by the method, there are few impurities and low cracks and warpage.
Reduced practical area of In_xAl_yGa_(1-xy)N (0 ≦
x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) Low cost single crystal substrate
Can be made with

[0143] According to the sixth aspect of the present invention, in the method for manufacturing a semiconductor substrate according to claim 4 or claim 5, wherein the first substrate is _{In t Al u Ga (1-} tu) N (0 ≤t
≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) Since it has a thermal expansion coefficient similar to that of a single crystal thin film, high-quality In _x Al _y Ga with a practical area in which cracks and warpage are reduced. _(1-xy) N
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) A single crystal substrate can be manufactured at low cost.

According to the seventh aspect of the present invention, In _x Al _y Ga _(1-xy) N (0 ≦ ₁₎ manufactured by the manufacturing method according to any one of the first to sixth aspects. x ≦ 1,
0 ≦ y ≦ 1, x + y ≦ 1) Since it is composed of a single crystal, GaN
Lattice matching with the system semiconductor, thermal conductivity, cleavage resistance, a large area with a conductive _{In x Al y Ga (1-} xy) N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) A single crystal substrate can be provided.

According to the invention of claim 8, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + a y ≦ 1) single crystal semiconductor substrate, the general formula _{In v Al w Ga (1-} VW) N containing at least one P-N junction
G represented by (0 ≦ v ≦ 1, 0 ≦ w ≦ 1, v + w ≦ 1)
Since the aN-based semiconductor stacked structure is formed by stacking, a semiconductor light emitting device including a high-quality crystal layer with reduced defects can be provided. Further, it is possible to provide a semiconductor laser having an electrode formed on the back surface of the substrate and having a cavity mirror formed by cleavage.

[Brief description of the drawings]

FIG. 1 is a view showing an example of a manufacturing process of a semiconductor substrate according to the present invention.

FIG. 2 is a diagram showing a specific example of a manufacturing process example of the semiconductor substrate shown in FIG.

[3] The second substrate polycrystalline _{In t Al u Ga (1-} tu) N
It is a figure which shows the example of a manufacturing process in the case of making into a (0 <= t <1,0 <= u <1, t + u <= 1) board | substrate.

[4] _{In r Al s Ga (1-} rs) N (0 ≦ r ≦ 1,0 ≦ s
≦ 1, r + s ≦ 1 ) single-crystalline thin film, polycrystalline In _t Al _u Ga
_(1-tu) N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) substrate, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) is a diagram showing an example of a manufacturing process in the case where the compositions of single crystals are all the same.

FIG. 5 is a diagram showing a specific example of a semiconductor light emitting device according to the present invention.

FIG. 6 is a diagram illustrating an example of a manufacturing process of a semiconductor substrate according to the present invention.

FIG. 7 is a diagram illustrating a specific example of a manufacturing process example of the semiconductor substrate illustrated in FIG. 6;

8 is a diagram showing a specific example of a manufacturing process example of the semiconductor substrate shown in FIG.

9 is a diagram showing a specific example of a manufacturing process example of the semiconductor substrate shown in FIG.

10 is a diagram showing a specific example of a manufacturing process example of the semiconductor substrate shown in FIG. 6;

FIG. 11 is a diagram showing a specific example of a semiconductor light emitting device according to the present invention.

FIG. 12 is a view showing a conventional semiconductor laser.

FIG. 13 is a diagram showing a conventional semiconductor laser.

[Explanation of symbols]

10 first substrate (single crystalline substrate) 11 GaN buffer layer _{12 In t Al u Ga (1} -tu) N (0 ≦ t ≦
1,0 ≦ u ≦ 1, t + u ≦ 1) Single-crystal thin film 13 Organic adhesive 14 Support substrate 15 Second substrate 16 Low melting point metal (indium or gallium) 17 In _x Al _y Ga _(1-xy) N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) single crystal substrate 20 (111) GaAs substrate 21 AlAs layer 22 GaAs layer 31 n-GaN buffer layer 32 n-Al _0.15 Ga _0.85 N cladding layer 33 n-GaN optical guide layer 34 In _0.15 Ga _0.85 N / In _0.02 Ga _0.98 N Multiple quantum well structure active layer 35 p-GaN optical guide layer 36 p-Al _0.15 Ga _0.85 N clad layer 37 p-GaN cap layer 38 protective layer made of SiO ₂ 39 p side ohmic electrode 40 n-side ohmic electrode 50 first substrate (single crystalline substrate) 51 GaN buffer layer _{52 in r Al s Ga (1} -rs) n (0 ≦ r ≦
1,0 ≦ s ≦ 1, r + s ≦ 1) Single-crystal thin film 53 Second substrate 54 In _x Al _y Ga _(1-xy) N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) single crystal 111 (0001) sapphire substrate 112 n-type GaN low-temperature buffer layer 113, 132 high-temperature buffer layer made of n-type GaN 114 SiO ₂ selective growth mask 115, 133 n− In _0.1 Ga _0.9 N crack prevention layer 116, 134 n-Al _0.14 Ga _0.86 N / GaN
MD-SLS (modulation-doped strained superlattice) cladding layer 117,135 n-GaN optical guiding layer 118,136 In _0.15 Ga _0.86 N / In _0.02 Ga
_0.98 N MQW active layer 120,138 p-GaN layer Light guide layer 121,139 p-Al _0.14 Ga _0.86 N / GaN M
D-SLS cladding layer 122, 140 p-type GaN layer cap layer 123, 143 P-side electrode 124, 142 SiO ₂ protective layer 125, 141 n-side electrode 131 (0001) plane GaN substrate

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H01S 5/343 H01S 5/343 F term (reference) 4G077 AA03 BE11 BE15 DB08 ED06 FJ03 FJ06 HA02 HA12 TA04 5F041 AA40 CA02 CA03 CA04 CA05 CA14 CA23 CA34 CA40 CA65 CA74 CA82 CA92 FF16 5F045 AA02 AA04 AB09 AB14 AB17 AB31 AB32 AC07 AC12 AC15 AC19 AD14 AE29 AF01 AF04 AF07 AF09 CA09 CA10 CA11 CA12 CB01 CB02 DA51 DA52 DA53 DA54 DA55 DA57 DA62 DA63 DA64 DB01 GH08 GH08 AA13 AA74 CA07 CB02 CB04 CB05 CB07 DA05 EA29 5F103 AA04 DD01 GG01 HH03 HH04 JJ01 JJ03 KK01 LL01 LL02 LL03 LL16 LL17 LL18 PP03 PP07 RR08 RR10

Claims (8)

[Claims] 1. A first substrate comprising In_rAl_sGa_(1-rs)N
(0 ≦ r ≦ 1,0 ≦ s ≦ 1, r + s ≦ 1)
And In_rAl_sGa_(1-rs)N (0 ≦ r ≦ 1,
0 ≦ s ≦ 1, r + s ≦ 1)_xAl_yGa
_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single connection
To a second substrate that has almost the same thermal expansion coefficient as the crystal
And the step of removing In from the first substrate._rAl_sGa_(1-rs)N (0
≤ r ≤ 1, 0 ≤ s ≤ 1, r + s ≤ 1) Separation of single crystal thin film
And the step of bonding In on the second substrate._rAl_sG
a_(1-rs)N (0 ≦ r ≦ 1, 0 ≦ s ≦ 1, r + s ≦ 1) unit
In the crystal thin film, In_xAl_yGa_(1-xy)N (0 ≦ x ≦ 1,
0 ≦ y ≦ 1, x + y ≦ 1) Single crystal epitaxial growth
And a step of performing In from the second substrate._xAl_yGa_{(1-x- y)}N
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) Separates a single crystal
In step_xAl_yGa_(1-xy)N (0 ≦ x ≦
1,0 ≦ y ≦ 1, x + y ≦ 1) Single crystal as semiconductor substrate
A method for manufacturing a semiconductor substrate, characterized by being manufactured by: 2. A method for manufacturing a semiconductor substrate according to claim 1, wherein the second substrate is a polycrystalline _{In t Al u Ga (1-} tu)
A method for manufacturing a semiconductor substrate, wherein the substrate is an N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) substrate. 3. The method for manufacturing a semiconductor substrate according to claim 2, wherein In _r Al _s Ga _(1-rs) N (0 ≦ r ≦ 1, 0 ≦ s
≦ 1, r + s ≦ 1 ) single-crystalline thin film, polycrystalline In _t Al _u Ga
_(1-tu) N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) substrate, In _x Al _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) A method for manufacturing a semiconductor substrate, wherein the compositions of single crystals are all the same. 4. The method according to claim 1, wherein the first substrate comprises In._tAl_uGa_(1-tu)N
(0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1)
Forming the first substrate and forming In from the first substrate._tAl_uGa_(1-tu)
N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) single crystal thin film
Separating and In_tAl_uGa_(1-tu)N (0 ≦ t ≦
1,0 ≦ u ≦ 1, t + u ≦ 1) Use single crystal thin film with low melting point metal
Attaching to the second substrate through
Pasted In_tAl_uGa_(1-tu)N (0 ≦ t ≦ 1,
0 ≦ u ≦ 1, t + u ≦ 1) Low melting point metal on single crystal thin film
At a temperature equal to or higher than the melting point of_xAl_yGa_(1-xy)N (0 ≦ x
≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) Epitaxy single crystal
And a step of growing In from the second substrate._xAl_yGa
_(1-xy)N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single connection
Separating the crystals at a temperature above the melting point of the low melting metal.
In_xAl_yGa_{(1-x -y)}N (0 ≦ x ≦ 1, 0 ≦ y ≦
1, x + y ≦ 1) Production of single crystal as semiconductor substrate
And a method for manufacturing a semiconductor substrate. 5. A first substrate _{In t Al u Ga (1-} tu) N
(0 ≦ t ≦ 1,0 ≦ u ≦ 1, t + u ≦ 1) forming a single-crystal thin film, the first substrate _{In t Al u Ga (1-} tu)
N (0 ≦ t ≦ 1,0 ≦ u ≦ 1, t + u ≦ 1) and the step of separating the single crystal thin _{film, In t Al u Ga (1} -tu) N (0 ≦ t ≦
1,0 ≦ u ≦ 1, t + u ≦ 1) a step of attaching the single crystal thin film to the second substrate via the molten metal Ga;
An In _t pasted in the substrate _{Al u Ga (1-tu)} N (0 ≦
to t ≦ 1,0 ≦ u ≦ 1, t + u ≦ 1) single-crystal thin film, at a temperature above the melting point of the metal _{Ga, In x Al y Ga (} 1-xy) N
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) a step of epitaxially growing a single crystal and cooling without solidifying the metal Ga, and a step of In _x Al _y Ga _(1-xy) from the second substrate N (0 ≦ x
≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) a step of separating the single crystal at a temperature equal to or higher than the melting point of metal Ga, thereby obtaining In _x Al _y Ga
_A method for manufacturing a semiconductor substrate, comprising using _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single crystal as a semiconductor substrate. 6. The method of claim 4 or the method for manufacturing a semiconductor substrate according to claim 5, wherein the first substrate is In _t Al _u G
a _(1-tu) N (0 ≦ t ≦ 1, 0 ≦ u ≦ 1, t + u ≦ 1) A method for manufacturing a semiconductor substrate, which has a thermal expansion coefficient similar to that of a single crystal thin film. 7. An In _x Al _y Ga manufactured by the manufacturing method according to any one of claims 1 to 6.
A semiconductor substrate comprising _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) single crystal. 8. The method of claim 7, wherein In _x Al _y Ga _(1-xy) N (0
≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) The general formula In _v including at least one PN junction on a single crystal semiconductor substrate
Al _w Ga ( _1-VW ) N (0 ≦ v ≦ 1, 0 ≦ w ≦ 1, v + w
<1) A semiconductor light emitting device comprising a stacked structure of a GaN-based semiconductor laminated structure represented by the formula (1).