【 Summary description 】 In modern C, N, B and other non-oxide high-tech refractory raw materials, atmospheric pressure sintered silicon carbide is extensive and economical, and can be said to be emery or refractory sand. Pure silicon carbide is colorless transparent crystal. So what is the material structure and characteristics of silicon carbide?
Material structure of atmospheric pressure sintered silicon carbide:
The atmospheric pressure sintered silicon carbide used in industry is light yellow, green, blue and black according to the type and content of impurities, and the purity is different and the transparency is different. The silicon carbide crystal structure is divided into six-word or diamond shaped plutonium and cubic plutonium-sic. Plutonium-sic forms a variety of deformation due to the different stacking order of carbon and silicon atoms in the crystal structure, and more than 70 kinds of deformation have been found. beta-SIC converts to alpha-SIC above 2100. The industrial process of silicon carbide is refined with high-quality quartz sand and petroleum coke in a resistance furnace. Refined silicon carbide blocks are crushed, acid-base cleaning, magnetic separation, screening or water selection to produce a variety of particle size products.
Material characteristics of atmospheric pressure sintered silicon carbide:
Silicon carbide has good chemical stability, thermal conductivity, thermal expansion coefficient, wear resistance, so in addition to abrasive use, there are many uses: For example, the silicon carbide powder is coated on the inner wall of the turbine impeller or cylinder block with a special process, which can improve the wear resistance and extend the life of 1 to 2 times. Made of heat-resistant, small size, light weight, high strength of high-grade refractory materials, energy efficiency is very good. Low-grade silicon carbide (including about 85% SiC) is an excellent deoxidizer for increasing steelmaking speed and easily controlling chemical composition to improve steel quality. In addition, atmospheric pressure sintered silicon carbide is also widely used in the manufacture of electrical parts of silicon carbon rods.
Silicon carbide is very hard. Morse hardness is 9.5, second only to the world's hard diamond (10), is a semiconductor with excellent thermal conductivity, can resist oxidation at high temperatures. Silicon carbide has at least 70 crystalline types. Plutonium-silicon carbide is a common isomer that forms at temperatures above 2000 and has a hexagonal crystalline structure (similar to wurtzite). Sintered silicon carbide under atmospheric pressure
Application of silicon carbide in semiconductor industry
The silicon carbide semiconductor industry chain mainly includes silicon carbide high-purity powder, single crystal substrate, epitaxial sheet, power components, module packaging and terminal applications.
1. Single crystal substrate Single crystal substrate is a semiconductor supporting material, conductive material and epitaxial growth substrate. At present, the growth methods of SiC single crystal include physical vapor transfer method (PVT method), liquid phase method (LPE method), and high temperature chemical vapor deposition method (HTCVD method). Sintered silicon carbide under atmospheric pressure
2. Epitaxial sheet Silicon carbide epitaxial sheet, silicon carbide sheet, single crystal film (epitaxial layer) with the same direction as the substrate crystal that has certain requirements for the silicon carbide substrate. In practical applications, wide band gap semiconductor devices are almost all manufactured in the epitaxial layer, and the silicon chip itself is only used as the substrate, including the substrate of GaN epitaxial layer.
3. High-purity silicon carbide powder High-purity silicon carbide powder is the raw material for the growth of silicon carbide single crystal by PVT method, and the purity of the product directly affects the growth quality and electrical characteristics of silicon carbide single crystal.
4. The power device is a wide-band power made of silicon carbide material, which has the characteristics of high temperature, high frequency and high efficiency. According to the operating form of the device, the SiC power supply device mainly includes a power diode and a power switch tube.
5. Terminal In third-generation semiconductor applications, silicon carbide semiconductors have the advantage of being complementary to gallium nitride semiconductors. Due to the high conversion efficiency, low heating characteristics, lightweight and other advantages of SiC devices, the demand of the downstream industry continues to increase, and there is a trend to replace SiO2 devices.
Post time: Oct-16-2023