CN-122013312-A - Method for controlling growth of silicon carbide crystal grains

Abstract

The invention relates to a method for controlling the growth of silicon carbide grains, which is characterized in that a carbon source and a silicon source are mixed and then are transported through a gas phase in a protective atmosphere, and react on a deposition plate to generate the silicon carbide grains. The crystal form, size and number of the crystal grains can be regulated and controlled by the proportion of raw materials, a temperature system and the reaction times. The invention can obtain monocrystalline or polycrystalline silicon carbide with low cost, the obtained silicon carbide crystal has high purity, wide size coverage range and high growth speed of the silicon carbide crystal in the growth process, and provides a new thought for controlling the growth of the silicon carbide crystal for the silicon carbide industry.

Inventors

• CHEN CHANGLIAN
• SUN WENYUE
• CHEN YONGZAI
• FENG JINGQIN
• FENG JINGYU

Assignees

• 湖北迪洁膜科技有限责任公司

Dates

Publication Date

20260512

Application Date

20260310

Claims (10)

1. 1. A method of controlling grain growth of silicon carbide comprising the steps of: 1) Mixing the raw materials, namely uniformly mixing a carbon source and a silicon source according to a preset proportion to obtain a raw material for growing silicon carbide grains; 2) And (3) growing silicon carbide grains, namely placing the raw materials into a sagger for growing the silicon carbide grains and uniformly spreading, covering a deposition plate, placing the sagger into a high-temperature furnace, synthesizing the silicon carbide grains according to a sectional heating-heat preservation system under a protective atmosphere, forming and growing the silicon carbide grains on the deposition plate, and cooling to obtain the silicon carbide grains.
2. 2. The method of controlling grain growth of silicon carbide according to claim 1, wherein the carbon source is an organic carbon source consisting of only C, H, O, N elements.
3. 3. The method of claim 1, wherein the silicon source is selected from one or more of silicon carbide, elemental silicon, silicon monoxide, silicon dioxide, silicon nitride.
4. 4. The method of controlling grain growth of silicon carbide according to claim 1, wherein the mixing method in step 1) is any one of dry ball milling, wet ball milling or spray granulation.
5. 5. The method for controlling grain growth of silicon carbide according to claim 4, wherein the dispersion medium added during the mixing is ethanol when wet ball milling is used.
6. 6. The method of controlling silicon carbide grain growth according to claim 1, wherein the mixing ratio of the carbon source to the silicon source satisfies a C/Si atomic ratio of 1:1 to 1:3.
7. 7. The method of claim 1, wherein the sagger and the deposition plate are each independently selected from a carbon material or a silicon carbide material.
8. 8. The method of claim 1, wherein the sectional temperature rise-holding system comprises a decomposition stage, a nucleation stage and a growth stage, which are performed sequentially, and parameters of the three stages are independently adjustable.
9. 9. The method according to claim 8, wherein the temperature rise rate in the decomposition stage is 10 to 15 ℃ per minute, the maximum temperature is 1100 to 1750 ℃, the holding time is 0.5 to 1.5 hours, the temperature rise rate in the nucleation stage is 5 to 10 ℃ per minute, the maximum temperature is 1850 to 2100 ℃, the holding time is 1 to 2 hours, the temperature rise rate in the growth stage is 1 to 5 ℃ per minute, the maximum temperature is 2100 to 2600 ℃, and the holding time is 1 to 4 hours.
10. 10. The method according to claim 1, wherein steps 1) and 2) are repeated 1 to 3 times, parameters of the sectional heating-thermal insulation system are adjusted in the repeated process, and the purity of the finally obtained silicon carbide crystal grain is greater than 99%, and the crystal form, size and number of the silicon carbide crystal grain are cooperatively regulated and controlled by the raw material proportion, the heating-thermal insulation system parameters and the repetition times.

Description

Method for controlling growth of silicon carbide crystal grains Technical Field The invention belongs to the technical field of new materials, and particularly relates to a method for controlling growth of silicon carbide grains, which is particularly suitable for large-scale preparation of high-performance silicon carbide single crystals or polycrystalline particles. Background Silicon carbide is an excellent non-oxide ceramic material with both structural and functional characteristics, has the characteristics of high temperature resistance, corrosion resistance, oxidation resistance, high mechanical strength, excellent heat conductivity and the like, has the core advantages of wide band gap, high breakdown field strength, high saturated electron drift rate and the like when being used as a semiconductor material, and has irreplaceable application prospect in the fields of modern industrial high-performance devices, structural parts and the like. However, the large-scale production of high quality silicon carbide grains has been limited by the inherent drawbacks of the prior art, principally in the following two respects: On the one hand, the mainstream Physical Vapor Transport (PVT) method needs to implement sublimation and recrystallization of silicon carbide raw materials at extremely high temperature of >2200 ℃, and has extremely high requirements on high temperature resistance and stability of a reaction chamber, a heating element and a heat insulation system, so that special equipment has complex structure, high manufacturing cost and huge energy consumption in the production process. The method is mainly used for growing bulk single crystals, is difficult to flexibly prepare discrete single crystals or polycrystalline particles with controllable morphology and size, and has poor economy. On the other hand, the high temperature chemical vapor deposition (HT-CVD) method adopts special gases such as silane (SiH 4), propane (C 3H8) and the like as reaction sources, the gases have extremely toxic and explosive characteristics, and complex safety protection and tail gas treatment systems are required to be equipped in the storage, transportation and use processes, so that the equipment investment and the operation cost are greatly increased, and serious potential safety hazards exist. Meanwhile, the technology has the core advantage that the film epitaxial growth can not realize the morphology and size regulation of discrete grains. Therefore, the prior art is difficult to meet the requirements of industrial production on a simple, economical, safe and controllable silicon carbide crystal grain preparation method due to high equipment and energy consumption cost or poor process safety and insufficient product controllability. The development of a silicon carbide grain growth technology based on safe and low-cost raw materials, simple process and easily-controlled parameters becomes a key for promoting the development of the silicon carbide industry. Disclosure of Invention The invention aims to solve the problems of high cost, poor safety, large control difficulty of crystal forms and sizes, insufficient purity and the like in the existing silicon carbide preparation technology, and provides a silicon carbide crystal grain growth method with simple process, low cost and strong product controllability. In order to achieve the above object, the present invention provides a method for controlling growth of silicon carbide grains, comprising the steps of: 1) Mixing the raw materials, namely uniformly mixing a carbon source and a silicon source according to a preset proportion to obtain a raw material for growing silicon carbide grains; 2) And (3) growing silicon carbide grains, namely placing the raw materials into a sagger for growing the silicon carbide grains and uniformly spreading, covering a deposition plate, placing the sagger into a high-temperature furnace, synthesizing the silicon carbide grains according to a sectional heating-heat preservation system under a protective atmosphere, forming and growing the silicon carbide grains on the deposition plate, and cooling to obtain the silicon carbide grains. Further, the carbon source is an organic carbon source composed of only C, H, O, N elements. Further, the silicon source is selected from one or more of silicon carbide, elemental silicon, silicon monoxide, silicon dioxide, and silicon nitride. Further, the mixing method in the step 1) is any one of dry ball milling, wet ball milling or spray granulation. Further, when wet ball milling is adopted, the dispersion medium added in the mixing process is ethanol. Further, the mixing ratio of the carbon source to the silicon source satisfies a C/Si atomic ratio of 1:1-1:3. The ideal stoichiometric ratio of silicon carbide (SiC) is C: si=1:1 (atomic ratio). If solid raw materials are mixed strictly according to the proportion, solid-solid direct reaction mainly occurs at high temperature, the product is eas