High-quality gallium nitride crystal grown based on HVPE equipment and preparation method thereof

Abstract

The invention discloses a preparation method for growing a high-quality gallium nitride crystal based on HVPE equipment. The preparation method comprises the following steps: S1, providing a sapphire substrate; s2, making a SiO2 cylinder-like layer on the sapphire substrate; s3, growing a gallium nitride nucleating layer on the SiO2 cylinder-like layer; s4, growing a three-dimensional distribution layer on the gallium nitride nucleating layer; s5, growing a two-dimensional distribution layer on the three-dimensional distribution layer; s6, growing an insertion layer on the two-dimensional distribution layer; s7, growing a two-dimensional distribution second layer on the insertion layer; and S8, growing a gallium nitride thick film layer on the two-dimensional distribution second layer. The method has the following beneficial effects that the stress is reduced by adding the SiO2-like column layer and doping the InGaN layer at the bottom of the grown GaN, so that the GaN crystal with extremely low dislocation and very small stress is obtained. According to the invention, easy self-stripping is realized, so that the GaN crystal with the thickness of more than 5mm can be obtained.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology, and in particular relates to a method for growing high-quality gallium nitride crystals based on HVPE equipment and a preparation method thereof. Background Art

[0002] Currently, GaN is a typical representative of the third generation of wide bandgap semiconductors and has been widely used in semiconductor lighting, microwave power devices, and power electronics, showing great application prospects. The most ideal substrate for growing GaN is naturally GaN single crystal material. Such homoepitaxial growth (i.e., the epitaxial layer and the substrate are made of the same material) can greatly improve the crystal quality of the epitaxial film, reduce dislocation density, increase device operating life, improve luminous efficiency, and increase device operating current density. However, GaN single crystal growth is difficult and expensive, and large-scale homoepitaxial growth is still not possible. Therefore, the current production of GaN single crystals still uses heteroepitaxial growth, such as on silicon substrates, sapphire substrates, and silicon carbide substrates.

[0003] Currently, virtually all commercial GaN substrates (wafers, substrates) are manufactured using HVPE. HVPE equipment directly grows thick GaN crystals on sapphire substrates using the chemical reaction formula (2Ga(l) + 2HCl(t) → 2GaCl(g) + H2(g)). Currently, the following major issues exist: 1. Self-exfoliation of thick GaN crystals is difficult, making it impossible to obtain GaN crystals thicker than 5mm. 2. Thick GaN crystals generate significant stress. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, the technical solution adopted by the present invention is: a preparation method for growing high-quality gallium nitride crystals based on HVPE equipment, comprising the following steps:

[0006] S1. Provide a sapphire substrate;

[0007] S2, making a SiO2 cylindrical layer on a sapphire substrate;

[0008] S3, growing a gallium nitride nucleation layer on the SiO2 cylindrical layer;

[0009] S4, growing a three-dimensional distribution layer on the gallium nitride nucleation layer;

[0010] S5. growing a two-dimensional distribution layer on the three-dimensional distribution layer;

[0011] S6, growing an insertion layer on the two-dimensional distribution layer;

[0012] S7, growing a two-dimensional distribution layer on the insertion layer;

[0013] S8, growing a thick gallium nitride film layer on the two-dimensional distribution two layers.

[0014] The specific method of S2 is that, through a PECVD device, first, the sapphire substrate is placed into the PECVD device, a 50-500 nm SiO2 film is formed by deposition, then the pattern is exposed, and then the pattern is developed to show the required pattern, and then cleaning and photoresist are performed, so as to finally achieve no solution residue and achieve an EPI-READY surface.

[0015] The insertion layer comprises a low-temperature indium gallium nitride layer, wherein the component of indium is less than 15%.

[0016] The SiO2 type cylindrical layer is a nano-pillar or a micro-pillar, the SiO2 type cylindrical layer is a SiO2 elliptical cylindrical layer or a SiO2 right cylindrical layer or a SiO2 irregular cylindrical layer, the size of the SiO2 type cylindrical layer is 100 nm-50 μm, and the height of the SiO2 type cylindrical layer is 50-500 nm.

[0017] The component of the gallium nitride nucleation layer comprises aluminum nitride and gallium nitride, the growth temperature is 500-1000 degrees Celsius, and the thickness is 1 nm-200 nm.

[0018] The three-dimensional distribution layer is a gallium nitride layer, the growth temperature is 1000-1060 degrees Celsius, the V / III ratio is 50-1000, and the thickness is 500 nm-10 μm.

[0019] The two-dimensional distribution one layer is a gallium nitride layer, the growth temperature is 1040-1120 degrees Celsius, the thickness is 250 nm-1 μm, and the V / III ratio is 500-5000; the two-dimensional distribution two layers is a gallium nitride layer, the growth temperature is 1040-1120 degrees Celsius, the thickness is 250 nm-1 μm, and the V / III ratio is 500-5000.

[0020] The insertion layer is a low-temperature indium gallium nitride layer, wherein the component of indium is less than 15%, and the growth temperature is 600-800 degrees Celsius.

[0021] The gallium nitride thick film layer has a growth temperature of 1060-1120 degrees Celsius, a thickness of 0.8 mm-10 mm, and a V / III ratio of 500-5000.

[0022] A high-quality gallium nitride crystal based on an HVPE device is grown by using the preparation method.

[0023] Compared with the prior art, the present application has the following beneficial effects: stress is reduced by adding a SiO2 type columnar layer and incorporating an InGaN layer at the bottom of the grown GaN, so that a GaN crystal with extremely low dislocation and very small stress is obtained. Easy self-stripping is realized by the present application, so that a GaN crystal with a thickness of more than 5 mm can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a structural schematic diagram of a gallium nitride crystal prepared by the present application;

[0025] Figure 2 is a stress test diagram of the present application. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0027] On the contrary, the present application covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present application as defined by the claims. Further, in order to make the public have a better understanding of the present application, some specific details are described in detail in the following detailed description of the present application. The present application can also be completely understood without the description of these details by those skilled in the art.

[0028] Reference Figure 1 A preparation method for growing a high-quality gallium nitride crystal based on an HVPE device, comprising the following steps:

[0029] S1, providing a sapphire substrate 11;

[0030] S2, forming a SiO2 type columnar layer 12 on the sapphire substrate 11;

[0031] S3, growing a gallium nitride nucleation layer 13 on the SiO2 type columnar layer 12;

[0032] S4, growing a three-dimensional distribution layer 14 on the gallium nitride nucleation layer 13;

[0033] S5, growing a two-dimensional distribution one layer 151 on the three-dimensional distribution layer 14;

[0034] S6, growing an insertion layer 16 on the two-dimensional distribution one layer 151;

[0035] S7, growing a two-dimensional distribution two layer 152 on the insertion layer 16;

[0036] S8, growing a gallium nitride thick film layer 17 on the two-dimensional distribution two layer 152.

[0037] The specific method of S2 is to first place the sapphire substrate 11 into the PECVD equipment through the PECVD equipment, form a 50nm-500nm SiO2 film by deposition, then expose the pattern, and then develop the pattern to show the required pattern, and then clean and photoresist, finally achieving no solution residue and achieving an EPI-READY surface state.

[0038] The insertion layer 16 comprises a low-temperature indium gallium nitride layer, wherein the indium content is less than 15%;

[0039] The SiO2-like cylindrical layer 12 is a nanocolumn or a microcolumn, the SiO2-like cylindrical layer 12 is a SiO2 elliptical cylindrical layer or a SiO2 regular cylindrical layer or a SiO2 irregular cylindrical layer, the size of the SiO2-like cylindrical layer 12 is 100nm-50μm, and the height of the SiO2-like cylindrical layer 12 is 50-500nm.

[0040] The components of the gallium nitride nucleation layer 13 include aluminum nitride and gallium nitride, the growth temperature thereof is 500-1000 degrees Celsius, and the thickness is 1 nm-200 nm.

[0041] The three-dimensional distribution layer 14 is a gallium nitride layer, with a growth temperature of 1000-1060 degrees Celsius, a V / III ratio of 50-1000, and a thickness of 500nm-10μm.

[0042] The two-dimensional distribution layer 151 is a gallium nitride layer, with a growth temperature of 1040-1120 degrees Celsius, a thickness of 250nm-1μm, and a V / III ratio of 500-5000; the two-dimensional distribution layer 152 is a gallium nitride layer, with a growth temperature of 1040-1120 degrees Celsius, a thickness of 250nm-1μm, and a V / III ratio of 500-5000.

[0043] The insertion layer 16 is a low-temperature indium gallium nitride layer, wherein the indium component is less than 15%, and the growth temperature thereof is 600-800 degrees Celsius.

[0044] The gallium nitride thick film layer 17 has a growth temperature of 1060-1120 degrees Celsius, a thickness of 0.8 mm-10 mm, and a V / III ratio of 500-5000.

[0045] A high-quality gallium nitride crystal grown based on HVPE equipment is prepared using the above-mentioned preparation method.

[0046] In this embodiment, a SiO2 cylindrical layer is used on a sapphire substrate to significantly reduce dislocations caused by the large heteroepitaxial lattice mismatch, achieving XRD002 values ​​of <35 arcsec and XRD102 values ​​of <35 arcsec, resulting in dislocations in the GaN crystals below 1E6, significantly improving the self-stripping performance of the GaN thick-film crystals. Furthermore, a low-temperature InGaN insertion layer is added to the two-dimensional distribution layer to reduce stress generated by GaN thick-film growth, with tested stress values ​​reaching 0. Through the method of the present invention, a GaN thick-film crystal with a low dislocation density is obtained.

[0047] See also Figure 2 Through Raman spectroscopy testing, the E2-high peak position of stress-free bulk GaN material is 568cm-1.

Claims

1. A method for growing high-quality gallium nitride crystals based on HVPE equipment, characterized in that: The following steps are involved: S1. providing a sapphire substrate (11); S2, forming a SiO2 cylindrical layer (12) on a sapphire substrate (11); S3, growing a gallium nitride nucleation layer (13) on the SiO2 cylindrical layer (12); S4, growing a three-dimensional distribution layer (14) on the gallium nitride nucleation layer (13); S5. growing a two-dimensional distribution layer (151) on the three-dimensional distribution layer (14); S6. growing an insertion layer (16) on the two-dimensionally distributed layer (151); S7, growing a two-dimensional distribution second layer (152) on the insertion layer (16); S8. Growing a gallium nitride thick film layer (17) on the two-dimensionally distributed second layer (152).

2. The method for growing high-quality gallium nitride crystals based on HVPE equipment according to claim 1, characterized in that: The specific method of S2 is to first place the sapphire substrate (11) into the PECVD equipment through the PECVD equipment, form a 50nm-500nm SiO2 film by deposition, then expose the pattern, and then develop the pattern to show the required pattern, and then clean and photoresist, finally achieving no solution residue and achieving an EPI-READY surface state.

3. The method for growing high-quality gallium nitride crystals based on HVPE equipment according to claim 1, characterized in that: The insertion layer (16) comprises a low-temperature indium gallium nitride layer, wherein the indium component is less than 15%.

4. The method for growing high-quality gallium nitride crystals based on HVPE equipment according to claim 1, wherein: The SiO2-like cylindrical layer (12) is a nanocolumn or a microcolumn, the SiO2-like cylindrical layer (12) is a SiO2 elliptical cylindrical layer or a SiO2 regular cylindrical layer or a SiO2 irregular cylindrical layer, the size of the SiO2-like cylindrical layer (12) is 100nm-50μm, and the height of the SiO2-like cylindrical layer (12) is 50-500nm.

5. The method for growing high-quality gallium nitride crystals based on HVPE equipment according to claim 1, characterized in that: The components of the gallium nitride nucleation layer (13) include aluminum nitride and gallium nitride, its growth temperature is 500-1000 degrees Celsius, and its thickness is 1nm-200nm.

6. The method for growing high-quality gallium nitride crystals based on HVPE equipment according to claim 1, characterized in that: The three-dimensional distribution layer (14) is a gallium nitride layer with a growth temperature of 1000-1060 degrees Celsius, a V / III ratio of 50-1000, and a thickness of 500nm-10μm.

7. The method for growing high-quality gallium nitride crystals based on HVPE equipment according to claim 1, characterized in that: The two-dimensional distribution layer (151) is a gallium nitride layer, the growth temperature is 1040-1120 degrees Celsius, the thickness is 250nm-1μm, and the V / III ratio is 500-5000; the two-dimensional distribution layer (152) is a gallium nitride layer, the growth temperature is 1040-1120 degrees Celsius, the thickness is 250nm-1μm, and the V / III ratio is 500-5000.

8. The method for growing high-quality gallium nitride crystals based on HVPE equipment according to claim 1, characterized in that: The insertion layer (16) is a low-temperature indium gallium nitride layer, wherein the indium component is less than 15%, and the growth temperature thereof is 600-800 degrees Celsius.

9. The method for growing high-quality gallium nitride crystals based on HVPE equipment according to claim 1, characterized in that: The gallium nitride thick film layer (17) has a growth temperature of 1060-1120 degrees Celsius, a thickness of 0.8mm-10mm, and a V / III ratio of 500-5000.

10. A method for growing high-quality gallium nitride crystals based on HVPE equipment, characterized in that: The method is prepared by the method according to any one of claims 1 to 9.

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