JP2005094037A - Manufacturing method of semiconductor light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor light emitting device in which the occurrence of crystal defect or dislocation based on the mismatching of lattice constant or the difference of thermal expansion coefficient is suppressed as much as possible and the crystal can be cleaved. <P>SOLUTION: The method has (A) a process of depositing a gallium nitride system compound semiconductor layer 3 on a semiconductor single crystal substrate 1 and removing the semiconductor single crystal substrate 1, thereafter, by using the residual gallium nitride system compound semiconductor layer 3 after removing the semiconductor crystal substrate as a new substrate, forming buffer layers 4, 5 consisting of the gallium nitride system compound semiconductor, and (B) a process of further growing a gallium nitride system compound semiconductor single crystal layer including at least an n-type layer 6 and a p-type layer 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a semiconductor light emitting device. More specifically, the present invention relates to a method for manufacturing a semiconductor light emitting device using a gallium nitride compound semiconductor suitable for blue light emission.

  Here, the gallium nitride compound semiconductor is a compound in which a group III element Ga and a group V element N or a part of a group III element Ga is substituted with another group III element such as Al or In, and / or Alternatively, it refers to a semiconductor formed of a compound in which a part of N of the group V element is substituted with another group V element such as P or As.

  A semiconductor light emitting element is a semiconductor element that generates light, such as a light emitting diode (hereinafter referred to as LED) having a double heterojunction such as a pn junction or a pin, a super luminescent diode (SLD), or a semiconductor laser diode (LD). Say.

  Conventional blue LEDs have lower brightness than red and green and have had difficulties in practical use. Recently, a low resistance p-type semiconductor layer using gallium nitride compound semiconductor and doped with Mg has been obtained. , The brightness has been improved and attracted attention.

A conventional gallium nitride LED has a structure as shown in FIG. 5, for example. In order to manufacture this LED, first, an organic metal and a carrier gas H ₂ are formed on a sapphire (Al ₂ O ₃ single crystal) substrate 21 at a low temperature of 400 to 700 ° C. by a metal organic compound vapor deposition method (hereinafter referred to as MOCVD method). trimethyl gallium is compound gas (hereinafter, TMG hereinafter), trimethyl aluminum (hereinafter, referred to as TMA), trimethyl indium (hereinafter, TMI hereinafter) supplies and ammonia _{(NH 3), Al x Ga} y in 1-xy (0 ≦ x <1, 0 <y ≦ 1, x + y ≦ 1) is formed to a thickness of about 0.01 to 0.2 μm, and then the same gas is supplied at a high temperature of 700 to 1200 ° C. A high-temperature buffer layer 23 made of Al _x Ga _y In _1-xy N is formed to a thickness of about 2 to 4 μm.

Next, an n-type clad for forming a double heterojunction is formed by supplying a gas in the same ratio as described above to form an n-type Al _x Ga _y In _1-xy N layer 24 having the same composition of about 0.1 to 0.3 μm. Form a layer. In order to form these n-type layers, in the case of a gallium nitride compound semiconductor, the property of becoming n-type without doping with n-type impurities is utilized.

Next, Al _p Ga _q In _1-pq N (0 ≦ p <1, 0 <), in which the amount of Al is decreased from the composition of the cladding layer and the amount of In is increased to make the band gap energy smaller than that of the cladding layer. An active layer 25 made of q ≦ 1, p + q ≦ 1, p <x, 1-pq> 1-xy) is formed.

Next, an organic material such as biscyclopentadienylmagnesium (hereinafter referred to as Cp ₂ Mg) or dimethylzinc (hereinafter referred to as DMZn) for Mg or Zn as a p-type impurity is added to the same source gas as that for forming the n-type cladding layer. A metal compound gas is added and introduced into the reaction tube to form a p-type cladding layer 26 made of p-type Al _x Ga _y In _1-xy N.

Further, in order to form the cap layer 27, the same gas as described above is supplied to vapor-phase grow the p-type Al _x Ga _y In _{1 -xy} N layer.

After that, a protective film such as SiO ₂ on the semiconductor growth layer over the entire surface, 400 to 800 ° C., subjected to annealing at about 20 to 60 minutes, p-type cladding made of p-type _{Al x Ga y In 1-xy} N The layer 26 is activated. Next, in order to form an n-type electrode after removing the protective film, a resist is applied and patterned, and as shown in FIG. 5, a part of each grown semiconductor layer is dry-etched by chlorine plasma or the like. The n-type Al _x Ga _y In _{1 -xy} N layer 23 is exposed. Next, a metal film such as Au or Al is formed by sputtering or the like to form both electrodes 28 and 29, and an LED chip is formed by dicing.

  Since a conventional semiconductor light emitting device using a gallium nitride compound semiconductor has a sapphire substrate on the back side and is an insulator, a complicated process such as etching is required to form an electrode on the back side.

  The sapphire substrate can withstand high temperatures and can be adjusted to relatively various crystal planes, so that it is advantageously used. However, the lattice constants of the sapphire substrate and the gallium nitride semiconductor crystal are 4.758７５ respectively. And 3.189%, and the coefficient of thermal expansion is also different. Therefore, as shown in FIG. 6A, dislocations and crystal defects are generated in the buffer layer in contact with the sapphire substrate, and the crystal defects are the active layer. There is also a problem that the gallium-based compound semiconductor single crystal layer progresses and the operating region becomes narrower, and the optical quality of the semiconductor layer also deteriorates.

  Furthermore, since a sapphire substrate cannot be cleaved and a semiconductor light emitting device chip cannot be produced by cleaving with the above-described structure, a device that requires two mirror surfaces with parallel end faces with high accuracy, such as a semiconductor laser. Has the problem of being unsuitable.

  An object of the present invention is to solve such problems and to provide a method for manufacturing a semiconductor light emitting device in which generation of crystal defects and dislocations based on mismatch of lattice constants and differences in thermal expansion coefficients is suppressed as much as possible.

  Still another object of the present invention is to provide a semiconductor light emitting device capable of obtaining a mirror surface of an end surface by cleaving using a gallium nitride compound semiconductor for a semiconductor light emitting device that requires two mirror surfaces parallel to the end surface, such as a semiconductor laser. It aims at providing the manufacturing method of an element.

  The method for producing a semiconductor light emitting device according to the present invention includes (A) removing a semiconductor crystal substrate through a step of forming a gallium nitride compound semiconductor layer on the semiconductor single crystal substrate and a step of removing the semiconductor single crystal substrate. Forming a buffer layer made of a gallium nitride compound semiconductor using the remaining gallium nitride compound semiconductor layer as a new substrate, and (B) gallium nitride including at least an n-type layer and a p-type layer And a step of further growing a system compound semiconductor single crystal layer.

  In the step of forming the buffer layer in the step (A), a low-temperature buffer layer made of a gallium nitride compound semiconductor is formed at a low temperature of 400 to 700 ° C., and a gallium nitride compound is further formed at a high temperature of 700 to 1200 ° C. It can be formed by depositing a high-temperature buffer layer made of a semiconductor.

  The gallium nitride compound semiconductor single crystal layer including at least an n-type layer and a p-type layer has a sandwich structure of an n-type cladding layer, an active layer, and a p-type cladding layer, and the n-type cladding layer and the p-type cladding layer By forming the high-temperature buffer layer and the new substrate with a semiconductor material having the same composition, all the thick layers forming the semiconductor light-emitting element have the same composition, and the crystal is neatly arranged to obtain a clean cleaved surface. It becomes easy to obtain.

  The remaining gallium nitride compound semiconductor layer in the step (A) has a thickness of 50 to 200 μm, so that it can be used as a stable substrate even if the semiconductor crystal substrate is removed, and it is difficult to be stressed. This is preferable because it can be a new substrate with a small amount.

  In the step (A), the low temperature buffer layer can be formed to a thickness of 0.01 to 0.2 μm, and the high temperature buffer layer can be formed to a thickness of 1 to 40 μm.

  According to the present invention, since the buffer layer is formed on the surface of the new substrate while the new substrate and the growing semiconductor layer are both gallium nitride compound semiconductors, they are epitaxially grown on the semiconductor crystal substrate, Even if slight crystal defects or distortions are generated in the new substrate formed by removing the semiconductor crystal substrate, it is absorbed by this buffer layer, and crystal defects are generated in the semiconductor stack that forms the light-emitting layer. Can be suppressed. Further, since the semiconductor light emitting device formed by this method is not an insulating substrate, the lower electrode may be formed on the back surface of the substrate, and the lower conductive type layer is exposed by etching from the upper surface side as in the prior art. There is no need to form electrodes. This eliminates the need for a dry etching process, simplifies the structural process, and does not cause characteristic deterioration due to resistance that is likely to occur during etching.

  Further, since the substrate is made of the same gallium nitride compound semiconductor layer as the thick layer such as a clad layer, the same kind of crystals are aligned and can be easily cleaved, and a mirror surface can be easily obtained. By making all the thick layers have the same composition, the cleaved surface can be made a clean mirror surface. As a result, a blue semiconductor laser can be easily obtained.

  Further, since the substrate is also made of a gallium nitride compound semiconductor layer, it is a semiconductor layer of the same type as the operation layer, and lattice matching is achieved by matching the lattice constant and the like, so that generation of crystal defects and dislocations can be prevented. As a result, the quality of the semiconductor layer is improved, and the light emission efficiency and lifetime of the element are improved.

  Next, a method for manufacturing the semiconductor light emitting device of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional explanatory view of an embodiment of a method for manufacturing a semiconductor light emitting device of the present invention, and FIGS. 2 to 4 are cross-sectional explanatory views of examples of a semiconductor light emitting device manufactured by the manufacturing method of the present invention.

  First, as shown in FIG. 1A, a low temperature buffer layer 2 and a high temperature buffer layer 3 made of a gallium nitride compound semiconductor layer are grown on the surface of a semiconductor single crystal substrate 1 by MOCVD.

  As the semiconductor single crystal substrate 1, for example, a GaAs single crystal substrate, a GaP single crystal substrate, an InP single crystal substrate, or a Si single crystal substrate each having a (111) crystal plane can be used. The reason why the semiconductor single crystal substrate having a crystal face of (111) is used is the crystal quality of the gallium nitride compound semiconductor layer. In addition, the use of the above-mentioned semiconductor single crystal substrate such as GaAs is relatively close to the gallium nitride compound semiconductor and the lattice constant compared to other materials, and the strain applied to the gallium nitride compound semiconductor layer can be reduced. Because.

In order to grow a semiconductor layer by the MOCVD method, a substrate is disposed in a reaction furnace, and a source gas for vapor phase growth, for example, an Al _x Ga _y In _1-xy N layer is grown by using a carrier gas. In H ₂ , TMA, which is an organometallic gas, is used as a source gas of Al, TMG, which is an organometallic gas, is used as a source gas of Ga, TMI, which is an organometallic gas, and NH ₃ is desired as a source gas of N It introduce | transduces at each flow volume so that it may become a ratio, and is made to react in a furnace. When growing a semiconductor layer having a different composition, the semiconductor layer having a desired composition can be grown by changing the introduction ratio or introducing a necessary source gas to the element having the composition and reacting it.

  The growth temperature at the time of growing a gallium nitride compound semiconductor is to grow by reacting at a high temperature of 700 to 1200 ° C. to grow a single crystal. However, when growing directly on a substrate of a different material having a different lattice constant or the like. Since the crystal directions of the single crystals do not completely coincide with each other, a low-temperature buffer layer 2 for growing as a polycrystalline film at a low temperature of 400 to 700 ° C. is interposed by about 0.01 to 0.2 μm, and 700 to 1200 ° C. is further formed thereon. It is preferable to grow the high temperature buffer layer 3 of about 50 to 200 μm at a high temperature. When the high temperature buffer layer 3 is grown, the low temperature buffer layer 2 grown as a polycrystalline film at a low temperature is also monocrystallized and aligned with the high temperature buffer layer 3.

  Next, as shown in FIG. 1B, mechanical polishing or chemical polishing is performed from the back side of the semiconductor single crystal substrate 1 to remove the semiconductor crystal substrate 1 and the low-temperature buffer layer 2. This mechanical polishing is performed by, for example, a polishing apparatus using diamond powder, and chemical polishing is performed by, for example, a mixed solution of sulfuric acid and hydrogen peroxide.

  Next, as shown in FIG. 1C, the remaining high-temperature buffer layer (gallium nitride compound semiconductor layer) 3 made of the gallium nitride compound semiconductor layer is disposed in the reactor as a new substrate. The low-temperature buffer layer 4 made of a gallium nitride compound semiconductor is provided in an amount of about 0.01 to 0.2 μm, and the high-temperature buffer layer 5 is provided in a range of 1 to 40 μm by the same method as described above. Since the substrate on which the gallium nitride compound semiconductor is grown is the same kind of gallium nitride single crystal layer, gallium nitride is used directly as the next cladding layer or active layer without providing the low temperature buffer layer 4 and the high temperature buffer layer 5. Although a compound compound semiconductor single crystal may be grown, the gallium nitride compound semiconductor layer substrate 3 as a new substrate here is formed on a different kind of semiconductor crystal substrate 1, and is a crystal based on lattice mismatch. Defects and dislocations may have occurred, and in that case, crystal defects and dislocations may also progress to the gallium nitride compound semiconductor single crystal layer formed thereon. Therefore, it is preferable to provide the low temperature buffer layer 4 and the high temperature buffer layer 5 again. The growth method and effects of the low temperature buffer layer 4 and the high temperature buffer layer 5 are the same as those of the low temperature buffer layer 2 and the high temperature buffer layer (gallium nitride compound semiconductor layer substrate) 3 in FIG.

  Next, as shown in FIG. 1D, an n-type cladding layer 6, an undoped or n-type or p-type active layer 7, a p-type cladding layer 8, and a cap layer 9 are sequentially formed. The cladding layers 6 and 8 are usually formed to a thickness of about 0.1 to 2 μm, and the active layer 7 is formed to a thickness of about 0.05 to 0.1 μm. The active layer 7 is formed very thin to the extent that crystal defects and dislocations cannot occur, but the cladding layer has a limit in making it thin. The thick layer together with the high temperature buffer layer 5 is preferably formed of a material having the same composition.

In order to make the semiconductor layer such as the above-described cladding layer an n-type layer, Si, Ge, and Sn are obtained by mixing them in the reaction gas as a gas such as SiH ₄ , GeH ₄ , and SnH ₄ . In order to form the p-type layer, the p-type layer can be formed by mixing Mg or Zn into the source gas as an organic metal gas of Cp ₂ Mg or DMZn. This p-type layer is provided with a protective film made of SiO ₂ or the like on the cap layer 9 and annealed at 400 to 800 ° C. or irradiated with an electron beam to combine with H (carrier gas). H ₂ and the H of the NH ₃ gas that is a reaction gas are separated to make Mg easy to move and lower resistance.

In this example, the active layer 7 has a double heterojunction structure in which both sides of the p-type layer and the n-type clad layer 6 and 8 are sandwiched between the active layer 7 and the clad layers 6 and 8 have a band gap larger than the band gap energy of the active layer 7. It consists of a material with energy. In order to increase the band gap energy with the aforementioned Al _x Ga _y In _1-xy N material, x can be increased and 1-xy can be decreased. By adopting a sandwich structure with the clad layers 6 and 8 having such band gap energy, carriers injected into the active layer are confined by an energy barrier that can be formed between the active layer and the clad layer as the light emitting layer. The establishment of luminescence recombination is significantly improved and the luminous efficiency is higher than the homojunction structure in which the pn junction is made of the same material. However, the manufacturing method of the present invention is not limited to such a double heterojunction structure, and can be similarly applied only by changing the composition of a semiconductor layer grown even in a homojunction or a heterojunction pn junction. Further, a semiconductor light emitting device having a refractive index waveguide structure can be manufactured in the same manner by forming a stripe groove with a semiconductor laser. The cap layer 9 is for reducing the contact resistance with the electrode metal 10 and is formed to a thickness of about 0.2 μm or less.

Next, as described above, a protective film such as SiO ₂ , Si ₃ N ₄ , or Al ₂ O ₃ is provided on the surface of the semiconductor layer and annealed at 400 to 800 ° C. for about 20 to 60 minutes, or protection is performed. Without providing a film, electron beam irradiation is performed directly from the surface with an acceleration voltage of about 3 to 20 kV. As a result, the junction between Mg and H, which are dopants in the p-type layer, is cut, activation is achieved, and the resistance of the p-type layer is reduced.

  Next, an electrode material such as Au or Al is formed by vapor deposition or sputtering, and a lower (n-side) electrode 11 is formed on the entire surface on the back side, and a light emitting area is secured on the front side in the case of an LED. In order to control the current injection region in the case of a semiconductor laser, the upper (p-side) electrode 10 is formed by patterning so as to remain only in the central portion, and then cleaved into each chip. A semiconductor light emitting element chip is formed as shown in a perspective view in FIG.

  Place this semiconductor light-emitting element chip on the lead frame, wire bond and mold with epoxy resin, then place the chip on the stem, wire bond and seal with cap to complete the laser diode To do.

  According to the present invention, after a gallium nitride compound semiconductor layer is grown on a semiconductor single crystal substrate, the semiconductor single crystal substrate is removed, and the gallium nitride compound semiconductor layer is used as a new substrate and an operating layer thereon. Since the single crystal layer of gallium nitride compound semiconductor is grown, the lattice constant and the thermal expansion coefficient are very close, and lattice defects and dislocations are hardly generated.

  On the other hand, a gallium nitride compound semiconductor used as a new substrate due to a lattice mismatch between the semiconductor single crystal substrate and the gallium nitride compound semiconductor layer used as a new substrate grown on the semiconductor single crystal substrate. There is a concern that a crystal defect occurs in the layer, and that the crystal defect spreads to the gallium nitride compound semiconductor single crystal layer as the operation layer, causing dislocations and crystal defects. This can be effectively prevented by providing a low temperature buffer layer and a high temperature buffer layer.

  Furthermore, by making the composition of the semiconductor single crystal layer of the buffer layer and the clad layer thicker than 1 μm the same, a clean cleaved surface can be obtained and a mirror surface can be easily obtained.

  Next, the production method of the present invention will be described in detail with more specific light-emitting elements.

Example 1
FIG. 2 is a cross-sectional explanatory view of a gallium nitride double heterojunction LED manufactured by the manufacturing method of the present invention. Al _x Ga _y In _1-xy N (0 ≦ x <1, 0 <y ≦ 1, 0 <x + y ≦ 1) is used as the gallium nitride compound semiconductor, and doubled by changing the ratio of Al, Ga, and In. A heterojunction is formed.

First, a gallium nitride system formed as a new substrate made of an n-type Al _x Ga _y In _1-xy N semiconductor layer formed to a thickness of 50 to 200 μm as shown in FIG. N-type Al _v Ga _w In _{1 -vw} N (0 ≦ v <1, 0 <w ≦ 1, 0 <v + w ≦ 1, v ≦ x, 1 at a low temperature of 400 to 700 ° C. on the surface of the compound semiconductor layer substrate 3. -Xy ≦ 1-vw) is grown by the MOCVD method at a temperature of about 0.01 to 0.2 μm, and then the gallium nitride compound semiconductor layer substrate 3 is formed at a high temperature of 700 to 1200 ° C. A high-temperature buffer layer 5 made of n-type Al _x Ga _y In _1-xy N having the same composition was provided to a thickness of about 1 to 40 μm. Further, an n-type cladding layer 6 made of n-type Al _x Ga _y In _1-xy N is provided at a thickness of about 0.1 to 2 μm at 700 to 1200 ° C., and non-doped Al _p Ga _q In _{1 -pq} N (0 ≦ p <1, 0 <q ≦ 1, 0 <p + q ≦ 1, p <x, 1-pq> 1-xy) The active layer 7 having a thickness of about 0.05 to 0.1 μm Further, a p _- type cladding layer 8 made of p-type Al _x Ga _y In _1-xy N was grown by ₁ to 2 μm. A cap made of Al _r Ga _s In _1-rs N (0 ≦ r <1, 0 <s ≦ 1, 0 <r + s ≦ 1, r ≦ x, 1-xy ≦ 1- _rs ). The layer 9 is provided with a thickness of about 0.2 μm.

  In the above structure, both the cladding layers 6 and 8 have the same composition, and these layers have a band gap energy larger than that of the active layer 7. That is, by increasing the amount of Al and decreasing the amount of In, a material having a large band gap energy is obtained, and the cladding layers 6 and 8 made of a material having a large band gap energy are made of a material having a small band gap energy. The structure is such that the active layer 7 is sandwiched, and carriers injected into the active layer are confined by an energy barrier to increase luminous efficiency.

  After that, as described above, the resistance of the p-type layer was reduced by electron beam irradiation, and an electrode was formed and cleaved to obtain a double heterojunction blue LED having a luminance of about 0.5 candela (cd). .

According to this embodiment, since the active layer made of a material having a small band gap energy is a double heterojunction having a sandwich structure, the light emission efficiency can be improved and the thick semiconductor layers such as the cladding layer and the buffer layer are the same. Since the semiconductor layers having different compositions are formed so as not to cause crystal defects, a semiconductor layer having a defect-free film quality is obtained and cleavage is further facilitated.
Example 2
FIG. 3 shows an example of the semiconductor laser type light emitting device. The layers are formed in the same manner as in Example 1 until the formation of the layers and the electrodes. The upper part of this is etched into a mesa shape. With such a structure, the current can be concentrated only in the central portion of the active layer, and since the end face is mirrored by cleavage, it can be reflected and oscillated by the end face, and the output is 0. A blue semiconductor laser type light emitting element of about 2 mW was obtained.
Example 3
FIG. 4 shows an embodiment of a pn junction LED. A low-temperature buffer layer 4 made of n-type GaN is provided on a gallium nitride compound semiconductor layer substrate 3 at a temperature of about 0.01 to 0.2 μm, and a high-temperature buffer layer 5 made of n-type GaN. The n-type layer 12 made of n-type Al _t Ga _1-t N (0 ≦ t <1) is grown to a thickness of about 1 to 2 μm. A p _- type layer 13 composed of p _- type In _u Ga _1-u N (0 ≦ u <1) is formed to a thickness of about 0.1 to 0.3 μm, respectively, and then p-type Al _z Ga _1-z N (0 ≦ 0). After forming a cap layer 14 of z <1), the p-type layer 13 is irradiated with an electron beam at an acceleration voltage of about 3 to 20 kV and annealed, and then the lower (n-side) electrode 11 and the upper (p) Side) Electrode 10 was formed to manufacture a heterojunction pn junction LED. With this heterojunction structure, the luminous efficiency increased, and a blue LED with a luminance of about 0.2 candela (cd) was obtained.

It is a figure which shows the manufacturing process of one Embodiment of the manufacturing method of the semiconductor light-emitting device of this invention. It is sectional explanatory drawing of LED manufactured by one Example of the manufacturing method of this invention. It is sectional explanatory drawing of the semiconductor laser manufactured by one Example of the manufacturing method of this invention. It is sectional explanatory drawing of LED manufactured by one Example of the manufacturing method of this invention. It is sectional explanatory drawing of the conventional GaN-type LED. It is a figure explaining the condition of the dislocation which generate | occur | produces in the buffer layer formed on the conventional sapphire substrate.

Explanation of symbols

1 Semiconductor single crystal substrate 3 Gallium nitride compound semiconductor layer (new substrate)
4 Low temperature buffer layer 5 High temperature buffer layer 6 n-type cladding layer 7 active layer 8 p-type cladding layer

Claims (5)

(A) The gallium nitride compound remaining after removing the semiconductor crystal substrate through a step of forming a gallium nitride compound semiconductor layer on the semiconductor single crystal substrate and a step of removing the semiconductor single crystal substrate Forming a buffer layer made of a gallium nitride compound semiconductor using the semiconductor layer as a new substrate, and (B) further growing a gallium nitride compound semiconductor single crystal layer including at least an n-type layer and a p-type layer A method for producing a semiconductor light-emitting device having a process.   In the step of forming the buffer layer in the step (A), a low-temperature buffer layer made of a gallium nitride compound semiconductor is formed at a low temperature of 400 to 700 ° C., and a gallium nitride compound is further formed at a high temperature of 700 to 1200 ° C. The method for producing a semiconductor light emitting device according to claim 1, wherein a high temperature buffer layer made of a semiconductor is formed.   The gallium nitride compound semiconductor single crystal layer including at least an n-type layer and a p-type layer has a sandwich structure of an n-type cladding layer, an active layer, and a p-type cladding layer, and the n-type cladding layer and the p-type cladding layer 3. The method of manufacturing a semiconductor light emitting device according to claim 2, wherein the high temperature buffer layer and the new substrate are formed of a semiconductor material having the same composition.   4. The method for manufacturing a semiconductor light emitting device according to claim 1, wherein the remaining gallium nitride compound semiconductor layer in the step (A) has a thickness of 50 to 200 [mu] m.   5. The semiconductor light emitting device according to claim 2, 3, or 4, wherein the low temperature buffer layer in the step (A) is formed to a thickness of 0.01 to 0.2 μm and the high temperature buffer layer is formed to a thickness of 1 to 40 μm. Manufacturing method.

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