Growth method of large-sized silicon carbide polycrystalline ceramic adjustable in electrical resistivity

Abstract

The invention relates to a growth method of a large-sized silicon carbide polycrystalline ceramic adjustable in electrical resistivity. A silicon carbide raw material is contained by adopting a graphite crucible, the graphite crucible is composed of a graphite crucible top cover and a graphite crucible body, the inner surface of the graphite crucible is provided with a carbon film layer, the silicon carbide raw material is put in the graphite crucible body, the graphite crucible top cover is put on, the graphite crucible body is put in a growth furnace, the bottom and / or the lower portion of the graphite crucible body is located in a heating zone to make the temperature at the bottom of the graphite crucible body higher than that of the graphite crucible top cover, and a silicon carbide polycrystalline ceramic material grows on the surface of the carbon film layer by adopting a physical gaseous phase transmission method or a high-temperature chemical vapor deposition method. The growth method is simple, and the silicon carbide polycrystalline ceramic is more excellent in performance, better in uniformity, better in compactness, higher in purity and better in thermal conductivity compared with a traditional silicon carbide ceramic.

Description

technical field [0001] The invention belongs to the field of silicon carbide materials, in particular to a method for growing silicon carbide polycrystalline ceramics based on a physical vapor transport method. Background technique [0002] Silicon carbide (SiC) materials mainly include two categories: single crystal and ceramics. Silicon carbide single crystal has the advantages of large band gap, high thermal conductivity, high electron saturation drift rate, high critical breakdown electric field, low dielectric constant, and good chemical stability. Irradiation semiconductor devices, ultraviolet detectors and short-wave light-emitting diodes have broad application prospects, and devices made of them can be used in high-temperature environments above 600 °C. Silicon carbide ceramics have the characteristics of high temperature strength, strong oxidation resistance, good wear resistance, good thermal stability, small thermal expansion coefficient, high thermal conductivit...

AI Technical Summary

Problems solved by technology

[0003] At present, the density, purity and thermal conductivity of traditional silicon carbide ceramics limit its wider application. Although silicon carbide single crystal has excellent performance and relatively mature preparation, it is expensive, and it is still difficult to be widely used in general. field

SiC single crystal thermal conductivity and other properties are better than SiC ceramics, but the production cost of high-quality single crystal silicon carbide is high and the process is complicated, which greatly limits the application of single crystal silicon carbide

In contrast, the preparation cost of polycrystalline silicon carbide ceramics is low and the process is relatively simple, but its density, purity and resistivity are difficult to meet the existing needs

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