Silicon carbide, also known as SiC, is a basic semiconductor material composed of pure silicon and pure carbon. We can dope SiC with nitrogen or phosphorus to form N - type semiconductors, or with beryllium, boron, aluminum or gallium to form P - type semiconductors. Different types of silicon carbide can be generated by doping different materials.
The simplest method of manufacturing silicon carbide is to melt silica sand and carbon at a high temperature of up to 2500 degrees Celsius. Silicon carbide usually contains impurities of iron and carbon, but pure SiC crystals are colorless and are formed when silicon carbide sublimes at 2700 degrees Celsius. Therefore, after heating, these crystals are deposited on graphite at a lower temperature. This process is also called the Lely method. That is, the granite crucible is heated to a very high temperature by induction to sublime the silicon carbide powder. A graphite rod with a lower temperature is suspended in the gaseous mixture, which itself enables the deposition of pure silicon carbide and the formation of crystals, thus producing silicon carbide.
Silicon carbide mainly has the advantages of high thermal conductivity of 120 - 270 W/mK, low thermal expansion coefficient of 4.0x10^-6/°C, and high maximum current density. Combined, these advantages give silicon carbide very good electrical conductivity, which is very advantageous in some fields that require high current and high thermal conductivity. With the development of the times, silicon carbide has become an important role in the semiconductor industry, powering the power modules for all high - power and high - efficiency applications. Although silicon carbide is more expensive than silicon, SiC can achieve a voltage threshold of nearly 10 kV. Silicon carbide also has extremely low switching losses, which can support high operating frequencies and then achieve high efficiency. Especially in applications with an operating voltage of more than 600 volts, if properly implemented, silicon carbide devices can reduce the converter and inverter system losses by nearly 50%, reduce the size by 300%, and greatly reduce the overall system cost.
