Special graphite components: New track high-purity graphite support "field" in the third generation semiconductor field

At present, the domestic mainstream commercial silicon carbide single crystal growth is using PVT method. This method uses induction coil to heat, and the high-density graphite heating element will be heated under the action of eddy current. The silicon carbide (SiC) powder is filled with the bottom of the graphite crucible, the silicon carbide (SiC) seed crystal is bonded inside the graphite crucible cover which has a certain distance from the raw material surface, and then the graphite crucible as a whole is placed in the graphite heating body, and the raw material of silicon carbide (SiC) is placed in the high temperature zone by adjusting the temperature of the external graphite felt. The silicon carbide (SiC) seed is correspondingly in the low temperature region. In this process, the area composed of the crucible and the surrounding insulation material is the most important area for the growth of SiC single crystals, which is called the hot field area. At present, the international SiC single crystal growth furnace adopts intermediate frequency heating technology, which is characterized by the crystal growth chamber can reach a very high temperature (up to 3000 ° C), in this high temperature scenario, graphite and related products can withstand such high temperatures, and it does not react with SiC sublimate at such high temperatures. Therefore, the crucible and insulation materials used for growing SiC require the use of high-purity graphite and carbon-based products. High purity is a key requirement of semiconductor graphite, especially in the process of crystal growth, impurities in graphite is a key determinant of crystal quality, impurity content should be kept below 5 parts per million.

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Source: China Powder network