CN-122013306-A - Silicon carbide crystal growth method and device

Abstract

A growth method and a growth device of a silicon carbide crystal belong to the technical field of preparation of the silicon carbide crystal and comprise the following steps of obtaining core-shell particles and silicon carbide powder, wherein the core-shell particles comprise a core and a shell layer, the shell layer is coated outside the core, the core is germanium, the shell layer is silicon carbide, the core-shell particles and the silicon carbide powder are used as growth raw materials, and the silicon carbide crystal is grown by a PVT method to obtain the silicon carbide crystal, wherein the growth temperature is 2100-2300 ℃, the growth pressure is 5mbar-30mbar, and the growth time is 50-200 hours. According to the application, by adding core-shell particles with germanium as a core and silicon carbide as a shell into the growth raw material, the low-melting-point material germanium is completely coated by the high-melting-point material silicon carbide, so that the phenomenon of nonuniform release of germanium element in the growth process is avoided, and the quality of the silicon carbide crystal can be effectively improved while the production process is simple.

Inventors

• XU SUOCHENG
• CUI CAN

Assignees

• 浙江理工大学

Dates

Publication Date

20260512

Application Date

20260119

Claims (10)

1. 1. A method and a device for growing silicon carbide crystals are characterized by comprising the following steps: Obtaining core-shell particles and silicon carbide powder, wherein the core-shell particles comprise a core and a shell, the shell is coated outside the core, the core is germanium, and the shell is silicon carbide; and growing silicon carbide crystals by using core-shell particles and silicon carbide powder as growth raw materials through a PVT method to obtain the silicon carbide crystals, wherein the growth temperature of the silicon carbide crystals is 2100-2300 ℃ and the growth pressure is 5mbar-30mbar, and the growth time is 50-200 hours.
2. 2. The method for growing a silicon carbide crystal according to claim 1, wherein the particle diameter of the core is 5um to 30um, and the thickness of the shell layer is 5um to 40um.
3. 3. A method of growing silicon carbide crystals according to claim 2, wherein the core-shell particles have a particle size of 10um to 50um.
4. 4. A method of growing silicon carbide crystals according to any of the claims 1-3 wherein the mass ratio of core-shell particles to silicon carbide powder is determined according to the concentration of germanium to be doped in the silicon carbide crystals.
5. 5. A method for growing silicon carbide crystal according to claim 4, wherein said core-shell particles are mixed with silicon carbide powder in a mass ratio of 1:99 to 30:70.
6. 6. A method for growing a silicon carbide crystal according to any of claims 1 to 3 or 5 wherein said core-shell particles are obtained by fluidized bed chemical vapor deposition of a silicon carbide layer on the surface of a germanium seed crystal.
7. 7. A method of growing silicon carbide crystals according to claim 6, wherein the preparation of the core-shell particles comprises the steps of: placing germanium seed crystals into a fluidized bed reactor; Introducing a silicon source and a carbon source into the fluidized bed reactor; Carrying out vapor deposition reaction in a fluidized bed reactor to obtain a reaction product; Separating core-shell particles with proper particle size from the reaction product; Wherein the temperature of the vapor deposition reaction is controlled within the range of 600-900 ℃, the pressure is controlled within the range of 0.5-1 megapascal, and the carrier gas flow is within the range of 150-250L/min.
8. 8. The method for growing silicon carbide crystals as claimed in claim 7, wherein the step of separating core-shell particles having a suitable particle size from the reaction product comprises the steps of: discharging the reaction product from the fluidized bed reactor; core-shell particles with proper particle sizes are separated from the reaction product through screens with different thicknesses.
9. 9. The method for growing a silicon carbide crystal according to claim 7 or 8, wherein the silicon source comprises methyltrichlorosilane, trichlorosilane or dichlorosilane, the carbon source comprises ethylene or acetylene, and the germanium seed crystal has a particle size of 5um to 30um and a purity of more than 6n.
10. 10. A computer device comprising a memory, a processor and a computer program stored on the memory, characterized in that the processor executes the computer program to carry out the steps of the method according to any one of claims 1-9.

Description

Silicon carbide crystal growth method and device Technical Field The invention belongs to the technical field of preparation of silicon carbide crystals, and particularly relates to a growth method and device of silicon carbide crystals. Background Silicon carbide (SiC) crystals are third-generation wide-bandgap semiconductor core materials, have the advantages of large forbidden bandwidth, high thermal conductivity, high breakdown electric field strength, high electron saturation drift speed and the like, and are widely applied to the fields of power devices, radio frequency devices, optoelectronic devices and the like. Germanium (Ge) doping can optimize lattice matching, energy band structure and electrical property of silicon carbide (SiC) crystals, and improve device yield. At present, ge is mainly prepared by directly mixing Ge and SiC raw materials or pressing the raw materials into a block shape for crystal growth. For example, patent publication No. CN115161762B discloses a method for growing a silicon carbide ingot by using a germanium-silicon-carbon ternary alloy solid, comprising the steps of uniformly mixing carbon powder, silicon powder and germanium powder to form mixed powder, pressing the mixed powder into a cake, placing the mixed cake into a reaction furnace, firing the mixed cake to form the germanium-silicon-carbon ternary alloy solid, and growing a silicon carbide crystal by using the germanium-silicon-carbon ternary alloy solid as a raw material based on a PVT method to obtain the germanium-doped silicon carbide ingot, wherein the mass fraction ratio of Ge to C in the germanium-silicon-carbon ternary alloy solid is determined according to the lattice constant of a silicon carbide seed crystal used in the PVT method, so that the lattice constant of the germanium-silicon-carbon ternary alloy and the silicon carbide seed crystal is consistent. According to the method, the silicon carbide crystal is grown by taking the germanium-silicon-carbon ternary alloy solid as a raw material, so that a silicon carbide ingot with uniform doping germanium elements can be finally obtained, and the yield of germanium-doped silicon carbide products is improved. But the sublimation point of germanium (Ge) powder is about 1200 ℃ and the SiC growth temperature exceeds 2000 ℃. Germanium is volatilized and exhausted in the early growth stage, so that the longitudinal doping concentration is greatly reduced and the doping is uneven. There is a need to develop a method and apparatus for growing silicon carbide crystals to solve the problems of the prior art. Disclosure of Invention The invention aims to provide a growth method and a growth device of silicon carbide crystals, which are characterized in that a silicon carbide shell layer is coated outside a germanium core, so that low-melting-point material germanium is completely coated by high-melting-point material silicon carbide, and the phenomenon of nonuniform germanium element release in the growth process is avoided, so that the problem of nonuniform doping of the germanium-doped silicon carbide crystals in the background art is solved. In order to solve the technical problems, the specific technical scheme of the invention is as follows: A method and a device for growing silicon carbide crystals comprise the following steps: Obtaining core-shell particles and silicon carbide powder, wherein the core-shell particles comprise a core and a shell, the shell is coated outside the core, the core is germanium, and the shell is silicon carbide; and growing silicon carbide crystals by using core-shell particles and silicon carbide powder as growth raw materials through a PVT method to obtain the silicon carbide crystals, wherein the growth temperature of the silicon carbide crystals is 2100-2300 ℃ and the growth pressure is 5mbar-30mbar, and the growth time is 50-200 hours. Further, the particle size of the core is 5um-30um, and the thickness of the shell layer is 5um-40um. Further, the particle size of the core-shell particles is 10-50 um. Further, the mass ratio of the core-shell particles to the silicon carbide powder is determined according to the concentration of germanium that needs to be doped in the silicon carbide crystal. Further, the core-shell particles and the silicon carbide powder are mixed according to the mass ratio of 1:99-30:70. Further, the core-shell particles are obtained by coating a silicon carbide layer on the surface of the germanium seed crystal through fluidized bed chemical vapor deposition. Further, the preparation of the core-shell particles comprises the following steps: placing germanium seed crystals into a fluidized bed reactor; Introducing a silicon source and a carbon source into the fluidized bed reactor; Carrying out vapor deposition reaction in a fluidized bed reactor to obtain a reaction product; Separating core-shell particles with proper particle size from the reaction product; Wherein the temperature of the vapor deposi