CN100547816C - Non-polarized composite gallium nitride base substrate and production method - Google Patents

Abstract

The invention discloses a non-polar composite GaN-based substrate and a production method. The structure of the non-polarized GaN-based composite substrate is as follows: reflection/ohmic/stress buffer layers are stacked between the supporting substrate and the non-polarized GaN-based epitaxial layer. The main process steps for producing a non-polarized composite gallium nitride-based substrate are as follows: on the growth substrate, grow an intermediary layer (or crystal nucleus layer) and a non-polarized first gallium nitride-based epitaxial layer in sequence; Mask layer; etch mask layer to form GaN windows and mask layer bars; grow non-polarized second GaN-based epitaxial layer; laminate reflective/ohmic/stress buffer layers; bonding support substrate; lift-off growth Parts with cavities in the substrate, intermediary layer (or crystal nucleus layer), non-polarized first GaN-based epitaxial layer, mask layer strips, and non-polarized second GaN-based epitaxial layer , the portion of the non-polarized second GaN-based epitaxial layer without voids is exposed, and subjected to heat treatment.

Description

Non-polarized composite GaN-based substrate and production method

technical field

The invention discloses a non-polar compound gallium nitride base substrate, which belongs to the technical field of semiconductor electronics.

Background technique

Currently, in industry, c-sapphire substrate is used as one of the main growth substrates for growing GaN-based devices (including GaN-based LEDs). However, there are the following disadvantages: (1) There is a built-in polarization electric field in the GaN-based epitaxial layer, which reduces the combination efficiency of electrons and holes in the GaN-based epitaxial layer, thus reducing the GaN-based epitaxial layer. The internal quantum efficiency of the device. (2) Sapphire is a material with low thermal conductivity, and the heat dissipation problem of high-power devices needs to be solved.

In order to overcome the above-mentioned deficiencies, industries and research institutions adopt the following schemes. (1) In order to eliminate the built-in polarization electric field, the following growth substrates (including, but not limited to: gallium nitride substrate, aluminum nitride substrate, sapphire substrate, silicon substrate, zinc oxide substrate, silicon carbide Substrate, lithium aluminum oxide (LiAlO2) substrate, lithium gallium oxide (LiGaO2) substrate, boron nitride substrate, etc., wherein, the crystal lattice plane of described growth substrate includes, but not limited to, a-plane , m-plane, r-plane, etc.), using lateral epitaxy to grow non-polarized GaN-based devices [US patent application, publication number: 20050040385]. (2) In order to solve the problem of heat dissipation, a composite GaN-based substrate was proposed [Chinese patent application, application number: 200410086564.8].

However, the disadvantage of the lateral epitaxy method in solution (1) is that there are voids in the gallium nitride-based epitaxial layer, which is easy to deform at high temperature, and the device is easy to be broken down, etc. The composite GaN-based substrate in scheme (2) is polarized.

Therefore, there is a need for a solution that can simultaneously solve the above problems, that is, a non-polarized composite GaN-based substrate and a production method. The advantages of the non-polarized compound GaN-based substrate are as follows. There are no voids in the non-polarized compound GaN-based growth substrate, so it is not easy to deform at high temperature, and the device is not easy to be broken down. Non-polarized GaN-based composite growth substrates can be used to grow non-polarized GaN-based devices (including non-polarized GaN-based LEDs) with high thermal conductivity. Non-polarized GaN-based devices grown on non-polarized GaN-based composite growth substrates have high internal quantum efficiencies.

Contents of the invention

The present invention discloses non-polarized composite GaN-based substrates with low defect density. The structure of a specific implementation example of the non-polarized GaN-based composite substrate is as follows: the non-polarized GaN-based epitaxial layer is bonded on the supporting substrate. The structure of the second specific implementation example of the non-polarized GaN-based composite substrate is as follows: the non-polarized GaN-based epitaxial layer is bonded on the reflective/ohmic/stress buffer layer, and the reflective/ohmic/stress buffer layer The layers are bonded to a supporting substrate.

The main process steps of the first specific implementation example of manufacturing a non-polarized composite gallium nitride-based substrate are as follows: on the above-mentioned growth substrate, an intermediate intermediary layer (or crystal nucleus layer) and a non-polarized first GaN-based epitaxial layer. A mask layer is stacked on the non-polarized first GaN-based epitaxial layer, and the mask layer is etched to form GaN windows and mask layer strips. growing a non-polarized second GaN-based epitaxial layer, covering the mask layer strips, and continuing to grow the non-polarized second GaN-based epitaxial layer to a predetermined thickness. The above are the standard process steps of the lateral epitaxy method. Then, the following process steps are carried out: bonding the support substrate on the non-polarized second gallium nitride-based epitaxial layer, peeling off the above-mentioned growth substrate, intermediary layer or crystal nucleus layer, and the non-polarized first gallium nitride-based epitaxial layer. The gallium-based epitaxial layer, the mask layer strip, and the portion with voids in the non-polarized second gallium nitride-based epitaxial layer, and the portion without voids in the non-polarized second gallium nitride-based epitaxial layer is exposed, and heat treatment is performed . The first specific implementation example of forming a non-polarized composite GaN-based substrate.

The main process steps of the second specific implementation example of manufacturing a non-polarized composite gallium nitride-based substrate are as follows: on the above-mentioned growth substrate, an intermediate intermediary layer (or crystal nucleus layer) and a non-polarized first GaN-based epitaxial layer. A mask layer is stacked on the non-polarized first GaN-based epitaxial layer, and the mask layer is etched to form GaN windows and mask layer strips. growing a non-polarized second GaN-based epitaxial layer, covering the mask layer strips, and continuing to grow the non-polarized second GaN-based epitaxial layer to a predetermined thickness. The above are the standard process steps of the lateral epitaxy method. Then, the following process steps are performed: stacking a reflective/ohmic/stress buffer layer on the non-polarized second GaN-based epitaxial layer, bonding a support substrate on the reflective/ohmic/stress buffer layer, and peeling off the growth substrate , the intermediary layer or the crystal nucleus layer, the non-polarized first GaN-based epitaxial layer, the mask layer bar and the part with holes in the non-polarized second GaN-based epitaxial layer, and the non-polarized The portion without voids in the second GaN-based epitaxial layer is exposed and subjected to heat treatment. A second specific implementation example of forming a non-polarized composite GaN-based substrate.

The process steps of growing a GaN-based epitaxial layer and laminating and etching a mask layer thereon can be repeated many times [R. Liu, et al., 2005 China (Xiamen) International Semiconductor Lighting Forum, p. 112].

The purpose of the present invention and the various effects that can be achieved are as follows:

(1) An object of the present invention is to provide a non-polarized composite GaN-based substrate having a low defect density.

(2) The object of the present invention is to provide a method for producing a non-polarized composite GaN-based substrate.

(3) Due to the following reasons, the non-polarized compound gallium nitride-based substrate provided by the present invention has high quality:

(a) The portions of the original growth substrate and the non-polarized GaN-based epitaxial layer in which voids are present are lifted off to provide a void-free non-polarized GaN-based epitaxial layer.

(b) During heat treatment, since the binding force to the crystal lattice of the non-polarized GaN-based epitaxial layer (the part without voids) no longer exists, the non-polarized GaN-based epitaxial layer returns to normal crystal structure, lattice defects are further reduced.

(4) When growing a non-polarized GaN-based LED on a non-polarized GaN-based composite substrate, the reflective layer in the reflective/ohmic/stress buffer layer improves light extraction efficiency.

(5) The stress buffer layer in the reflective/ohmic/stress buffer layer relieves the stress of the thermal mismatch between the non-polarized second GaN-based epitaxial layer and the support substrate.

(6) Three methods are adopted to further reduce the stress of thermal mismatch between the non-polarized second GaN-based epitaxial layer and the supporting substrate.

(7) The present invention uses a silicon wafer or other materials with high thermal conductivity as the supporting substrate, and the heat conduction efficiency is high.

The present invention and its features and benefits will be better demonstrated in the following detailed description.

Description of drawings

FIG. 1 a shows a first embodiment of the non-polarized composite GaN-based substrate of the present invention.

Fig. 1b shows the process flow of the first embodiment of the non-polarized composite GaN-based substrate of the present invention.

Figure 1c and Figure 1d show schematic diagrams of the process flow of Figure 1b of the present invention.

Fig. 2a shows a second embodiment of the non-polarized composite GaN-based substrate of the present invention.

Fig. 2b shows the process flow for producing the second embodiment of the non-polarized composite GaN-based substrate of the present invention.

Figure 2c and Figure 2d show schematic diagrams of the process flow of Figure 2b of the present invention.

Detailed Description of Specific Implementation Examples and Invention

Although the specific implementation examples of the present invention will be described below, the following descriptions are only to illustrate the principles of the present invention, rather than limiting the present invention to the descriptions of the following specific implementation examples.

Note the following: In the present invention,

(1) The material of the supporting substrate is selected from a group of materials including, but not limited to: silicon wafers, aluminum nitride ceramics, metal thin films, alloy thin films, and the like. Bonding methods include, but are not limited to: metal bonding, vacuum evaporation, vacuum sputtering, electroless plating, electroplating, and the like.

(2) There are several ways to reduce the thermal mismatch stress between the non-polarized second GaN-based epitaxial layer and the support substrate, which method to choose depends on the non-polarized GaN composite The structure of the base substrate, the material of the supporting substrate, and the method of bonding.

(3) The material of the non-polarized first and second gallium nitride-based epitaxial layers is selected from a group of materials including, but not limited to: gallium nitride, aluminum nitride, indium gallium nitride, AlGaN, AlInGaN, etc.

(4) The lattice planes of the non-polarized first and second GaN-based epitaxial layers are the same. The lattice planes include, a-plane and m-plane.

(5) Methods of growing non-polarized first and second GaN-based epitaxial layers include, but are not limited to, MOCVD, molecular beam epitaxy (MBE), hydride vapor phase epitaxy (HPVE), and the like.

(6) The material of the growth substrate is selected from a group of materials including, but not limited to: gallium nitride, aluminum nitride, sapphire, silicon, zinc oxide, 4H- and 6H-silicon carbide, oxide Lithium Aluminum (LiAlO2), Lithium Gallium Oxide (LiGaO2), Boron Nitride, etc. The lattice plane of the growth substrate includes, but not limited to, a-plane, m-plane, r-plane, etc.

(7) The material of the mask layer is selected from a group of materials including, but not limited to: silicon dioxide (SiO2), silicon nitride (SiNx), tungsten (W), and the like.

(8) Etching the mask layer to form GaN windows and mask layer strips. Shapes of GaN window and mask layer stripes, including, but not limited to, stripe types, etc. The gallium nitride window size can be, but is not limited to, 1 micron to 30 microns. The size of the mask layer stripes may be, but not limited to, 1 micron to 100 microns.

(9) The reflective/ohmic/stress buffer layer has a single-layer or multi-layer structure. The material of each layer is selected from a group of materials including, but not limited to: distributed Bragg reflectors (DBR), gold, rhodium, nickel, platinum, palladium, indium, tin, silver, cadmium, and other metals Or alloys and combinations thereof, combinations including, but not limited to, nickel/gold (Ni/Au), palladium/gold (Pd/Au), palladium/nickel (Pd/Ni), gold tin, and the like. Methods for stacking reflective/ohmic/stress buffer layers include, but are not limited to, vacuum evaporation, vacuum sputtering, electroless plating, electroplating, epitaxial growth, and the like.

(10) In order to further reduce the lattice defect density of the non-polarized GaN-based epitaxial layer, an intermediary layer or a crystal nucleus layer is grown between the growth substrate and the first non-polarized GaN-based epitaxial layer. The material of the crystal nucleus layer is selected from a group of materials including, but not limited to: gallium nitride. The thickness of the crystal nucleus layer is between 1 nanometer and 100 nanometers, and it grows on the growth substrate.

(11) Lifting off the growth substrate, the intermediary layer or the crystal nucleus layer, the non-polarized first gallium nitride-based epitaxial layer, the mask layer strips and the non-polarized second gallium nitride-based epitaxial layer with voids until the void-free portion of the non-polarized second GaN-based epitaxial layer is exposed. Lift-off methods include, but are not limited to, precision mechanical grinding/polishing, selective wet or dry etching, laser lift-off (applied to transparent substrates, e.g., sapphire, etc.), and combinations thereof (e.g., precision mechanical lapping grow the substrate to a certain thickness, such as 5 microns, and then use wet or dry etching to remove the remainder).

(12) Heat treatment. The distribution of defects in the non-polarized second GaN-based epitaxial layer is not uniform. After peeling off the growth substrate, the intervening layer or the GaN core layer, the mask layer strips and the non-polarized second GaN-based epitaxial layer with voids, the external force causing the defect no longer exists. Therefore, during the heat treatment, the portion of the non-polarized second GaN layer without voids returns to a normal crystal structure, and the lattice defect density of the non-polarized GaN-based epitaxial layer is further reduced.

FIG. 1 a shows the first specific implementation example of the non-polarized GaN-based composite substrate of the present invention, the structure of which is: a non-polarized GaN-based epitaxial layer 102 is bonded on a supporting substrate 101 .

Fig. 1b shows the process flow of the first embodiment of the non-polarized composite GaN-based substrate of the present invention. The process steps from step 111 to step 114 of the process flow are the same as those of the previous lateral epitaxy method, see Chinese patent application [application number: 02145890.1] and the above-mentioned US patent application [publication number: 20050040385] for details.

Step 111 of the process flow: preparing a growth substrate. Growth substrates include, but are not limited to, gallium nitride, aluminum nitride, sapphire, silicon, zinc oxide, 4H- and 6H-silicon carbide, lithium aluminum oxide (LiAlO2), lithium gallium oxide (LiGaO2), boron nitride, wait. The lattice plane of the growth substrate includes, but not limited to, a-plane, m-plane, r-plane, etc. In order to further improve the quality of the non-polarized first GaN-based epitaxial layer, the surface of the growth substrate can be etched into a textured structure [Chinese patent application, application number: 200510008931.7].

A specific implementation example of step 111 of the process flow: a commercial r-plane sapphire substrate is used. The preparation steps include, but are not limited to, cleaning and heat treatment, the heat treatment temperature being higher than 900°C.

Step 112 of the process flow: growing a non-polarized first GaN-based epitaxial layer on the surface of the growth substrate (or the surface with the textured structure). In order to further improve the quality of the non-polarized first GaN-based epitaxial layer, an intermediary layer or a crystal nucleus layer can be grown on the growth substrate first, and then a non-polarized epitaxial layer can be grown on the intermediary layer or the crystal nucleus layer A first GaN-based epitaxial layer.

The first specific implementation example of the process flow step 112: using MOCVD, grow a layer of gallium nitride substrate with a thickness between 1 nm and 90 nm on the r-plane sapphire growth substrate (at a temperature of 400-900 ° C). Nucleation layer. The material of the crystal nucleus layer includes, but is not limited to, gallium nitride. An a-plane non-polarized first GaN-based epitaxial layer is grown on the crystal nucleus layer. A specific implementation example of growing a non-polarized a-plane first gallium nitride-based epitaxial layer: growing a non-polarized a-plane at a temperature above about 1000° C. and at a pressure less than 1 atmosphere, with an appropriate V/III ratio The thickness of the first GaN-based epitaxial layer is 1-5 microns.

A second specific implementation example of process flow step 112: using MBE, grow an aluminum nitride buffer layer on an m-plane 6H-silicon carbide growth substrate, and then grow an m-plane first gallium nitride-based epitaxial layer.

Step 113 of the process flow: laminating a mask layer and etching the mask layer to form GaN windows and mask layer strips. Materials for the mask layer include, but are not limited to, silicon dioxide (SiO 2 ), silicon nitride (SiNx), tungsten (W), and the like. Shapes of GaN window and mask layer stripes include, but are not limited to, stripes, and the like.

A specific implementation example of step 113 of the process flow: use PECVD technology to stack silicon dioxide mask layers, and use photolithography and HF etching to form GaN windows and mask layer strips. The size of the GaN window is, but not limited to, 1 micron to 30 microns. The size of the mask layer stripes is, but not limited to, 1 micron to 100 microns. A more specific implementation example: Etching the silicon dioxide mask layer to form a 2-micron wide GaN window and an 8-micron wide mask layer strip, the direction of the mask layer strip is along the non-polarized first GaN-based epitaxy The (0001) direction of the layer.

Laminating and etching masking layers to form windows and masking layer bars is a well-established technique.

Step 114 of the process flow: growing a non-polarized second GaN-based epitaxial layer. In the gallium nitride window, the non-polarized gallium nitride-based epitaxial layer grows vertically upward until it reaches the level of the mask layer strip. On the one hand, it continues to grow upward, and on the other hand, it begins to grow laterally on the mask layer strip until The stripes meet at the top of the mask layer to form a void, and continue to grow upward to form a void-free top layer of the non-polarized second GaN-based epitaxial layer.

Process flow step 115: bonding the support substrate on top of the non-polarized second GaN-based epitaxial layer. Materials for supporting substrates include, but are not limited to, silicon wafers, aluminum nitride ceramics, metal thin films, alloy thin films, and the like. Bonding methods include wafer bonding, vacuum evaporation, vacuum sputtering, electroless plating, electroplating, etc. There are three ways to reduce the stress of the thermal mismatch between the non-polarized second GaN-based epitaxial layer and the support substrate: Method 1: Etching one side of the support substrate into a textured structure, and then bonding the non-polarized second GaN-based epitaxial layer The top layer of the GaN-based epitaxial layer is on the textured side of the support substrate. Method 2: Etching the top layer of the non-polarized second GaN-based epitaxial layer into a textured structure, and then bonding the support substrate on top of the textured structure of the non-polarized second GaN-based epitaxial layer layer. Method 3: Etch both the side of the supporting substrate and the top layer without voids of the non-polarized second GaN-based epitaxial layer into a textured structure, and then bond the textured side of the supporting substrate on the non-polarized on the textured top layer of the second GaN-based epitaxial layer. Which method to choose depends on the material of the supporting substrate and the method of bonding.

Step 116 of the process flow: peeling off the growth substrate, the intermediate medium layer or the crystal nucleus layer, the non-polarized first GaN-based epitaxial layer, the mask layer strips, and the strips of the non-polarized second GaN-based epitaxial layer There are hollow parts. The void-free portion of the non-polarized second GaN-based epitaxial layer is exposed. Lift-off methods include, but are not limited to, precision mechanical grinding/polishing, selective wet or dry etching, laser lift-off (applied to transparent substrates such as sapphire), and combinations thereof.

A first specific implementation example of step 116 of the process flow: precision mechanically grind the growth substrate to a certain thickness, such as 5 microns, and then use wet or dry etching to remove the rest.

A second specific implementation example of step 116 of the process flow: laser lift off the sapphire growth substrate, and then use wet or dry etching to remove the rest.

Process flow step 117 . heat treatment. During the heat treatment, because the growth substrate, the mask layer strip, and the non-polarized second GaN-based epitaxial layer with voids have been peeled off, the external force causing the defect no longer exists, and the non-polarized second gallium nitride-based epitaxial layer has voids. The portion without voids in the GaN-based epitaxial layer returns to a normal crystal structure during heat treatment, and the lattice defect density of the non-polarized GaN-based epitaxial layer is further reduced.

Figure 1c and Figure 1d show schematic diagrams of the process flow of Figure 1b of the present invention. An intermediary layer or crystal nucleus layer 122 is grown on the growth substrate 121 , and a non-polarized first GaN-based epitaxial layer 123 is grown on the intermediary layer or crystal nucleus layer 122 . GaN windows 124 and mask layer strips 125 are formed on the non-polarized first GaN-based epitaxial layer 123 . A non-polarized second GaN-based epitaxial layer 127 is grown on GaN window 124 and mask layer strip 125 to form cavity 126 . The support substrate 128 is stacked on top of the non-polarized second GaN-based epitaxial layer 127 without voids. peeling off the growth substrate 121, the intermediary layer or the crystal nucleus layer 122, the first non-polarized GaN-based epitaxial layer 123, the mask layer strips 125, and the non-polarized second GaN-based epitaxial layer 127 After the portion with voids, the bonded support substrate 128 shown in Figure 1d and the portion 129 without voids of the non-polarized second GaN-based epitaxial layer are formed, which is the embodiment of the present invention shown in Figure 1a The first concrete implementation example of a non-polarized GaN-based composite substrate.

Fig. 2 a shows the second specific implementation example of the non-polarized GaN-based composite substrate of the present invention, its structure is: reflective/ohmic/stress buffer layer 202 is stacked on the non-polarized GaN-based epitaxial layer 203 and the support substrate 201. Wherein, the reflective/ohmic/stress buffer layer 202 and the non-polarized GaN-based epitaxial layer 203 can be conductive or non-conductive. When a non-polarized GaN-based composite substrate has a conductive reflective/ohmic/stress buffer layer and a conductive non-polarized GaN-based epitaxial layer, and the support substrate 201 is non-conductive, the non-polarized Polarized composite GaN-based substrates can be used to manufacture novel vertical GaN-based LEDs [Chinese patent application, application number: 200510000296.8].

Fig. 2b shows the process flow for producing the second embodiment of the non-polarized composite GaN-based substrate of the present invention. The process flow steps 211 , 212 , 213 , 214 , 215 , 216 , 217 are respectively the same as the process flow steps 111 , 112 , 113 , 114 , 115 , 116 , 117 of FIG. 1 b. Between process flow steps 214 and 215, a process flow step 235 is added: layer reflective/ohmic/stress buffer layer on the non-polarized second GaN-based epitaxial layer. Then, the support substrate is bonded on the reflective/ohmic/stress buffer layer. The reflective/ohmic/stress buffer layer has a single-layer or multi-layer structure. Materials for each layer structure include, but are not limited to, distributed Bragg reflectors (DBR), gold, rhodium, nickel, platinum, palladium, indium, tin, silver, cadmium, and other metals or alloys and combinations thereof, combinations including, but not Limited to, nickel/gold (Ni/Au), palladium/gold (Pd/Au), palladium/nickel (Pd/Ni), gold tin, etc. Methods for stacking reflective/ohmic/stress buffer layers include, but are not limited to, vacuum evaporation, vacuum sputtering, electroless plating, electroplating, epitaxial growth, and the like.

In order to further reduce the stress of thermal mismatch between the non-polarized second GaN-based epitaxial layer and the support substrate, one of the following methods can be used: Method 1: Etching one side of the support substrate into a textured structure, and then, A reflective/ohmic/stress buffer layer is bonded to the textured side of the support substrate. Method 2: Etching the void-free top layer of the non-polarized second GaN-based epitaxial layer into a textured structure, and then bonding the reflective/ohmic/stress buffer layer on the non-polarized second GaN-based epitaxial layer layer on top of the textured structure. Method 3: Etch both the side of the support substrate and the void-free top layer of the non-polarized second GaN-based epitaxial layer into a textured structure, and then bond the reflective/ohmic/stress buffer layer on the support substrate Between the textured side and the textured top layer of the non-polarized second GaN-based epitaxial layer.

Figure 2c and Figure 2d show schematic diagrams of the process flow of Figure 2b of the present invention. An intermediary layer or crystal nucleus layer 222 is grown on the growth substrate 221 , and a non-polarized first GaN-based epitaxial layer 223 is grown on the intermediary layer or crystal nucleus layer 222 . GaN windows 224 and mask layer strips 225 are formed on the non-polarized first GaN-based epitaxial layer 223 . A non-polarized second GaN-based epitaxial layer 227 is grown on GaN window 224 and mask layer strip 225 to form cavity 226 . The reflective/ohmic/stress buffer layer 228 is stacked on top of the non-polarized second GaN-based epitaxial layer 227 without voids. A support substrate 229 is laminated on the reflective/ohmic/stress buffer layer 228 . Stripping the growth substrate 221, the intermediary layer or the crystal nucleus layer 222, the non-polarized first GaN-based epitaxial layer 223, the mask layer strips 225, and the strips of the non-polarized second GaN-based epitaxial layer 227 After the portion with voids, the void-free portion 231 of the bonded support substrate 229, reflective/ohmic/stress buffer layer 228, and non-polarized second GaN-based epitaxial layer shown in FIG. 2d is formed. , which is the second specific implementation example of the non-polarized composite GaN-based substrate of the present invention shown in FIG. 2a.

The above specific description does not limit the scope of the present invention, but only provides some specific illustrations of the present invention. Accordingly, the scope of the present invention should be determined by the claims and their legal equivalents, rather than by the above detailed description and implementation examples.

Claims (10)

1. A non-polarized compound gallium nitride-based substrate, comprising: (a) a supporting substrate; (b) a non-polarized gallium nitride-based epitaxial layer; the non-polarized gallium nitride-based epitaxial layer is bonded to the support substrate. 2. The non-polarized composite gallium nitride-based substrate of claim 1, further comprising a reflective/ohmic/stress buffer layer; said reflective/ohmic/stress buffer layer is stacked on said non-polarized nitrided between the Ga-based epitaxial layer and the supporting substrate. 3. The non-polarized composite GaN-based substrate of claim 1, wherein the material of the supporting substrate is selected from a group of materials comprising: silicon, silicon carbide, Aluminum nitride, zinc oxide, metals, alloys. 4. The non-polarized GaN-based composite substrate of claim 1, wherein the material of the non-polarized GaN-based epitaxial layer is selected from a group of materials comprising: nitrogen GaN, InGaN, AlGaN, AlInGaN. 5. The non-polarized GaN-based composite substrate of claim 1, wherein the lattice plane of the non-polarized GaN-based epitaxial layer comprises an a-plane or an m-plane. 6. The non-polarized composite GaN-based substrate of claim 2, wherein the structure of the reflective/ohmic/stress buffer layer comprises a single-layer or multi-layer structure. 7. The non-polarized composite gallium nitride-based substrate of claim 6, wherein the material of each layer of said reflective/ohmic/stress buffer layer is selected from a group of materials, the group Materials include: distributed Bragg reflectors, metals or combinations thereof; said metals include: gold, rhodium, nickel, platinum, palladium, titanium, indium, tin, silver, cadmium; said combinations include: nickel gold, palladium gold , palladium nickel, gold tin. 8. The non-polarized GaN-based composite substrate of claim 2, wherein said reflective/ohmic/stress buffer layer and said non-polarized GaN-based epitaxial layer are electrically conductive. 9. A method for producing a non-polarized composite gallium nitride-based substrate, the process steps comprising: (a) stacking an intermediate intermediary layer or a crystal nucleus layer on the growth substrate; (b) growing a non-polarized first gallium nitride-based epitaxial layer on the intermediate medium layer or the crystal nucleus layer; (c) laminating a mask layer on the non-polarized first GaN-based epitaxial layer; (d) etching said mask layer to form gallium nitride windows and mask layer strips; (e) growing a non-polarized second GaN-based epitaxial layer on the GaN window and mask layer strip; (f) bonding the support substrate on the second non-polarized gallium nitride-based epitaxial layer; the bonding method includes: vacuum evaporation, vacuum sputtering, electroless plating, electroplating, metal bond combine; (g) peeling off the growth substrate, the intermediary layer or the crystal nucleus layer, the non-polarized first GaN-based epitaxial layer, the mask layer strips, and the A portion with voids in the non-polarized second GaN-based epitaxial layer; a portion without voids in the non-polarized second GaN-based epitaxial layer is exposed; (h) heat treatment. 10. The method for producing a non-polarized composite GaN-based substrate according to claim 9, further comprising, laminating a reflective/ohmic/stress buffer layer on said non-polarized second GaN-based epitaxial layer and said between the supporting substrates; wherein, the method for stacking the reflective/ohmic/stress buffer layer includes: vacuum evaporation, vacuum sputtering, electroless plating, electroplating, and epitaxial growth.

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