Due to its special structure, graphite products have many characteristics such as high temperature resistance, thermal shock resistance, electrical conductivity, lubricity, chemical stability and plasticity. Graphite products, such as graphite rings and graphite boats, have a wide range of applications. International experts once predicted that "the 20th century will be the century of silicon, and the 21st century will be the century of carbon".
The development of semiconductors is inseparable from the application of graphite materials in the semiconductor industry. In the semiconductor industry, a large number of high-purity graphite materials are used in the heating system of single crystal furnaces. In semiconductor wafer processing (including zone melting, epitaxy, contour processing, etc.), graphite materials are auxiliary tools and parts, and semiconductor silicon wafers used in the production of polysilicon materials are used as auxiliary tools and parts. Graphite products used in electronic engineering, like large graphite block, must first be applied in the semiconductor industry. Entering the 21st century, the photovoltaic industry has developed rapidly, and the production and market of polycrystalline silicon ingot materials used for solar cells have experienced rapid growth.
The graphite product parts used in the Czochralski single crystal furnace, like isostatic graphite block are consumable parts, which are processed from a variety of high-purity graphites. Graphite parts such as graphite crucibles use high-purity fine-structure graphite; graphite heaters use high-purity isotropic graphite; graphite insulating cover and graphite cover use high-purity graphite particle structure. In the production of polycrystalline silicon ingot units, there are several components that require graphite material. In particular, the heating material used in the ingot furnace heater - high-purity graphite, and the thermal insulation material - high-purity carbon felt insulation material, are indispensable and important supporting materials in polysilicon ingot equipment.
Due to the high heating temperature of the ingot furnace heater (over 1600°C), the heating material cannot react with the silicon material and will not pollute the silicon material, and must be used in vacuum and inert gas. a long time. Heaters are based on usage conditions, such as metallic tungsten, molybdenum and non-metallic graphite. However, tungsten and molybdenum are expensive and difficult to process, and graphite can be processed into various shapes of graphite products. In addition, graphite also has the characteristics of small thermal inertia, fast heating, high temperature resistance, thermal shock resistance, large radiation area, high heating efficiency, and stable performance. Because of this, graphite material has become the preferred heating material in ingot furnace heaters.