CN111354628B

CN111354628B - Method for manufacturing gallium nitride growth substrate

Info

Publication number: CN111354628B
Application number: CN202010201435.8A
Authority: CN
Inventors: 石恒业; 邵永亮; 张保国; 胡海啸; 李仕蛟
Original assignee: Shandong Keheng Crystal Material Technologies Co ltd
Current assignee: Shandong Keheng Crystal Material Technologies Co ltd
Priority date: 2020-03-20
Filing date: 2020-03-20
Publication date: 2022-06-10
Anticipated expiration: 2040-03-20
Also published as: CN111354628A

Abstract

The invention relates to a method for manufacturing a gallium nitride growth substrate, belonging to the technical field of crystal material growth. The manufacturing method of the growth substrate comprises the steps of depositing a layer of silicon on a substrate crystal material through MOCVD, then evaporating a layer of metal gallium on the silicon layer in an evaporation mode, then introducing oxygen atmosphere to oxidize the silicon layer and the gallium layer in a high-temperature environment, and then etching the oxide layer by using hydrofluoric acid to form a gallium nitride growth buffer layer.

Description

Method for manufacturing gallium nitride growth substrate

Technical Field

The invention relates to the technical field of crystal material growth, in particular to a manufacturing method of a gallium nitride growth substrate.

Background

Third generation semiconductor materials, represented by gallium nitride, can emit blue light having a wavelength shorter than infrared light due to a wide bandgap. Meanwhile, the gallium nitride also has the characteristics of high electron mobility, high breakdown voltage, stable chemical property, high temperature resistance, corrosion resistance and the like, and is very suitable for manufacturing anti-radiation, high-frequency, high-power and high-density integrated electronic devices and blue, green and ultraviolet optoelectronic devices. Therefore, gallium nitride has wide application prospects in the aspects of semiconductor light-emitting diodes, laser diodes, ultraviolet detectors, high-energy high-frequency electronic devices and the like.

At present, the research of GaN growth becomes a hot spot of dispute research at home and abroad, but most of GaN films can only be grown by adopting a heterogeneous substrate due to the lack of a homogeneous substrate, and a layer of GaN film is heteroepitaxially grown by adopting an MOCVD method for facilitating nucleation. The existing processing method is to deposit a layer of TiN on the surface of the GaN film, and generate a porous structure of TiN nano-grids on the surface of the substrate through annealing treatment, so as to achieve the purpose of preparing the porous substrate.

Disclosure of Invention

In order to solve the problems in the prior art, the invention designs a manufacturing method of a gallium nitride growth substrate with low dislocation density and low growth stress, which comprises the steps of depositing a silicon layer with the thickness of 3-5 mu m on a crystal substrate material in A, MOCVD equipment;

B. evaporating, namely taking out the crystal material of the silicon layer deposited in the step a, putting the crystal material into an evaporator, and evaporating a layer of gallium on the silicon layer;

C. oxidizing, namely oxidizing the evaporated silicon layer in a high-temperature closed environment in an oxygen atmosphere to oxidize the silicon layer into silicon oxide and oxidize the gallium layer into gallium oxide;

D. etching, namely etching the silicon oxide layer and the gallium oxide layer on the surface of the crystal substrate material by using hydrofluoric acid;

E. and cleaning, namely, sequentially carrying out ultrasonic cleaning on the etched growth substrate in ethanol, acetone and deionized water, and drying.

Further, the crystal substrate material in step a may be selected from, but not limited to, aluminum oxide and silicon carbide.

Further, the oxygen atmosphere in the step C is one of oxygen and argon, oxygen and nitrogen or oxygen and carbon dioxide.

Further, the step A deposits the silicon layer at the reaction temperature of 660-700 ℃ by introducing silicon source gas comprising silane or silicon tetrachloride or dichlorosilane into the reactor.

Further, the temperature of the oxidation treatment in the step C is 500-759 ℃.

And further, the growth substrate in the step E is sequentially washed in three liquids for 5-20 minutes.

Compared with the prior art, the manufacturing method of the gallium nitride growth substrate has the advantages that a layer of gallium metal film is covered on the silicon layer in an evaporation mode, and evaporation can be carried out at different deposition rates, different substrate temperatures and different steam molecule incidence angles to form a film in an evaporation mode, so that films with different microstructures and crystal forms can be obtained, the purity of the film is very high, the thickness and components of the film can be detected and controlled on line easily, the highest thickness control precision can reach the monomolecular level, few pollutants are discharged, the method is basically free of pollution of three wastes, and the method is free of pollution of three wastes; moreover, the silicon oxide layer and the gallium oxide layer are corroded by hydrofluoric acid, most of silicon dioxide can be corroded, the dislocation density of a growth substrate and the residual stress of a growth crystal are reduced, and high-quality gallium nitride single crystal is favorably grown; meanwhile, the method designed by the invention is simple to operate, and the prepared buffer substrate is uniform and has good repeatability.

Drawings

FIG. 1 is a flow chart of the fabrication of a substrate

FIG. 2 is SEM photograph of etched surface of a GaN growth substrate in example 1

FIG. 3 is a SEM image of the etched surface of a GaN growth substrate in example 2

FIG. 4 is SEM image of etched surface of GaN growth substrate in example 3

FIG. 5 is a SEM image of the surface of KOH-NaOH mixed alkali etched

Detailed Description

The invention is further described with reference to the following figures and specific embodiments. The technical solutions in the embodiments of the present invention are clearly and completely described, and the described embodiments are only some embodiments, but not all embodiments, of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The invention designs a first embodiment of a manufacturing method of a gallium nitride growth substrate, in the embodiment, the manufacturing steps of the growth substrate are shown in figure 1, specifically, A, depositing a silicon layer, and depositing a silicon layer with the thickness of 5 microns on a silicon carbide crystal substrate material in MOCVD equipment by introducing silicon source gas containing silane into a reactor at the reaction temperature of 700 ℃;

C. oxidizing, namely oxidizing the silicon layer into silicon oxide and the gallium layer into gallium oxide in a sealed environment at 759 ℃ in the atmosphere of oxygen and argon after evaporation;

E. and (3) cleaning, namely, sequentially carrying out ultrasonic cleaning on the etched growth substrate in ethanol, acetone and deionized water, sequentially cleaning in three liquids for 20 minutes, and drying.

In order to verify the difference between the method and the existing mature method for judging dislocation density and dislocation type, a GaN epitaxial layer is epitaxially grown on a silicon carbide crystal material by using a traditional method, the GaN epitaxial layer is placed in a Ni crucible and is corroded by KOH-NaOH mixed alkali at the corrosion temperature of 500 ℃ for 30 minutes, and an SEM picture is taken, as shown in FIG. 5, the SEM picture of the substrate prepared by the embodiment is taken, as shown in FIG. 2, and by comparing the FIG. 2 with the FIG. 5, it can be seen that the buffer substrate prepared by the method designed by the invention is basically the same as the traditional mature method, has two pits in size and has a hexagonal appearance. In addition, the Raman test results show that the stress is 1.156 GPa.

Example 2

The invention designs a second embodiment of a manufacturing method of a gallium nitride growth substrate, in the embodiment, the manufacturing steps of the growth substrate are shown in figure 1, specifically, A, depositing a silicon layer, and depositing a silicon layer with the thickness of 3 microns on a silicon carbide crystal substrate material in MOCVD equipment by introducing silicon source gas containing silane into a reactor at the reaction temperature of 660 ℃;

C. oxidizing, namely oxidizing the evaporated silicon layer in a closed environment at 500 ℃ in the atmosphere of oxygen and carbon dioxide to oxidize the silicon layer into silicon oxide and oxidize the gallium layer into gallium oxide;

E. and cleaning, namely, sequentially carrying out ultrasonic cleaning on the etched growth substrate in ethanol, acetone and deionized water, sequentially cleaning in three liquids for 5 minutes, and drying.

The SEM image taken is shown in fig. 3, and the raman test result shows that the magnitude of the stress is 0.574 GPa.

Example 3

The invention designs a third embodiment of a manufacturing method of a gallium nitride growth substrate, in the embodiment, the manufacturing steps of the growth substrate are shown in figure 1, specifically, A, depositing a silicon layer, and depositing a silicon layer with the thickness of 4 microns on a silicon carbide crystal substrate material in MOCVD equipment by introducing silicon source gas containing silane into a reactor at the reaction temperature of 680 ℃;

C. oxidizing, namely oxidizing the silicon layer into silicon oxide and the gallium layer into gallium oxide in a closed environment at 650 ℃ in the atmosphere of oxygen and nitrogen after evaporation;

D. etching treatment, namely etching the silicon oxide layer and the gallium oxide layer on the surface of the crystal substrate material by using hydrofluoric acid;

E. and cleaning, namely, sequentially carrying out ultrasonic cleaning on the etched growth substrate in ethanol, acetone and deionized water, sequentially cleaning in three liquids for 10 minutes, and drying.

The SEM image taken is shown in fig. 4, and the raman test result shows that the stress is 0.742 GPa.

The above description is only for the preferred embodiment of the present invention, and should not be taken as limiting the scope of the invention, which is defined by the appended claims and the description of the invention.

Claims

1. A manufacturing method of a gallium nitride growth substrate is characterized by comprising the steps of depositing a silicon layer with the thickness of 3-5 microns on a crystal substrate material in A, MOCVD equipment;

B. evaporating, namely taking out the crystal material of the silicon layer deposited in the step A, and putting the crystal material into an evaporator to evaporate a layer of gallium on the silicon layer;

2. The method according to claim 1, wherein the crystalline substrate in step A is selected from the group consisting of alumina and silicon carbide.

3. The method of claim 1 or 2, wherein the oxygen atmosphere in step C is one of oxygen plus argon, oxygen plus nitrogen, or oxygen plus carbon dioxide.

4. The method of claim 1, wherein the silicon layer is deposited in step A by introducing a silicon source gas comprising silane or silicon tetrachloride or dichlorosilane into the reactor at a reaction temperature of 660-700 ℃.

5. The method for preparing a gallium nitride growth substrate according to claim 1, wherein the temperature of the oxidation treatment in step C is 500-759 ℃.

6. The method for preparing a gallium nitride growth substrate according to claim 1, wherein the growth substrate is sequentially washed in three liquids for 5-20 minutes in step E.