Application of graphite in semiconductor and photovoltaic industries

The process of application market development and expansion

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 Czochralski single crystal furnaces. It is also used as auxiliary tools and components in the processing of semiconductor silicon wafers (including zone melting, epitaxy, shape processing, etc.); as auxiliary tools and components in the production of polysilicon materials for semiconductor silicon wafers.

Graphite products for electronic engineering are firstly used in the semiconductor industry. In the 21st century, the photovoltaic industry has developed rapidly, and the production and market of polycrystalline silicon ingot materials for solar cells have increased by leaps and bounds, which also provides a new market with broad development prospects for graphite products in the photovoltaic industry. Ingot polysilicon, an important raw material for solar cell silicon wafers, has begun to use a large number of high-purity and high-quality graphite materials in the ingot furnace of its production device.

Semiconductor Application Market Overview of Graphite Products

The graphite parts used in the Czochralski single crystal furnace are a kind of consumable parts, which are processed from various high-purity graphites. For example, the graphite crucible and other graphite parts use high-purity fine-grained graphite; the graphite heater uses high-purity isotropic graphite; the graphite insulation cover and graphite cover use high-purity medium-grained graphite.

Market Overview of Graphite Products for Solar Cell Applications

In the production of ingot polysilicon equipment, graphite materials are required for several components. In particular, the heating material used in the ingot furnace heater - high-purity graphite, and the heat insulating material used - high-purity carbon felt heat insulating material are all important and indispensable supporting materials for ingot polysilicon equipment at present.

Since the heating temperature of the ingot furnace heater is very high (over 1600°C), its heating material is required to not react with the silicon material and cause no pollution to the silicon material, so it can be used in a vacuum and inert atmosphere for a long time. There are metal tungsten, molybdenum and non-metallic graphite for the heaters that can be selected according to the conditions of use. Because tungsten and molybdenum are expensive and difficult to process, graphite has a wide range of sources and can be processed into various shapes.

In addition, graphite has the characteristics of small thermal inertia, rapid heating, high temperature resistance, good thermal shock resistance, large radiation area, high heating efficiency, and stable basic performance. Because of this, graphite material has become the preferred heating material in ingot furnace heaters. Ingot furnace heaters have strict requirements on thermal insulation materials. It must be a material with high temperature resistance, low density, low thermal conductivity, less heat storage, good thermal insulation effect, less outgassing, light weight and small expansion coefficient. Therefore, high-purity carbon felt is the most ideal among many refractory insulation materials.

The above mentioned two types of graphite products used in the semiconductor and photovoltaic industry were mainly imported from abroad (or provided by foreign-funded enterprises in mainland China) a few years ago. But due to the joint efforts of China's graphite industry, semiconductor material industry, electronic industry equipment industry, China's own production of these two types of graphite supporting both in manufacturing technology, or in the application of technology have made great progress, the market pattern has also been greatly changed.

This also provides new opportunities for China's graphite industry to develop new markets in this respect. But at the same time, it is also necessary to see that while the market of large size and high purity isotropic graphite in China is rapidly increasing, China's manufacturing technology in this area is still not adapted to aspects, technology is still a big gap with foreign advanced countries.

As an important basic equipment material in microelectronics and photovoltaic industry, graphite products need continuous technological progress in China. It is imperative to strengthen cooperation with the semiconductor industry and silicon material manufacturing industry for photovoltaic cells, and further invest in the development of high-grade graphite products supporting them.