Chances and challenges of graphite-High purity graphite

With the rapid increase of my country’s integrated circuit market and photovoltaic product market, the rapid development of microelectronics and optoelectronics industries has a great demand for high-purity graphite, especially “three-high graphite”. The development of the semiconductor and photovoltaic industries, especially the rapid changes in the output and market of polycrystalline silicon ingot materials for solar cells, has provided graphite products with a new market with broad prospects in these two fields. It also marks a new step forward for high-purity, high-quality graphite carbon graphite material products from the traditional application market to the electronic engineering application market.

Because high-carbon graphite materials have good high temperature resistance and chemical stability, graphite materials are widely used to make graphite bowls, graphite heaters and Polycrystalline mold, heat treatment mold, heat shield, heat preservation cover, graphite cover plate, etc. Graphite components used in Czochralski single crystal furnaces are vulnerable parts, and the demand for components processed from various high-purity graphites continues to increase. In the production of ingot polysilicon equipment, graphite is used as a heating material, and heat insulating materials are indispensable supporting materials. At present, graphite products used in the semiconductor and photovoltaic industries in my country require large-scale, high-purity, high-density, high-strength, fine-grained, and isotropic graphite to increase rapidly.

Application of pure graphite

(1) Carbon graphite materials in the semiconductor industry: The development of semiconductors is inseparable from the application of graphite materials in the semiconductor industry. Graphite products for electronic engineering are firstly applied in the semiconductor industry. Graphite parts used in Czochralski single crystal furnaces are a type of consumable parts, which are processed from various high-purity graphites. For example, the graphite crucible and other graphite components are made of high-purity fine-grained graphite; the graphite heater is made of high-purity isotropic graphite; the graphite insulation cover and graphite cover are made of high-purity medium-grained graphite. It is used as an auxiliary tool and component in the processing of semiconductor silicon wafers (including zone melting, epitaxy, shape processing, etc.); it is used as an auxiliary tool and component in the production of polysilicon materials for semiconductor silicon wafers.

(2) Solar cell application of graphite products: Graphite material has low thermal penetration, can be heated rapidly, has a large radiation area for high temperature (over 1600°C), high heating efficiency, and stable performance. Therefore, graphite materials are required for multiple components in the production of ingot polysilicon equipment. In particular, the heating material used in the ingot furnace heater – high-purity graphite, and the heat insulation material used – high-purity carbon felt insulation material are important and indispensable supporting materials for ingot polysilicon equipment.

Since the heating temperature of the ingot furnace heater is very high (over 1600 °C), its heating material is required not to react with the silicon material, not to pollute the silicon material, and can be used in a vacuum and an inert atmosphere for a long time. The available heaters that meet the conditions of use include metal tungsten, molybdenum, and non-metallic graphite. 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. For this reason, graphite materials have become the preferred heating material in ingot furnace heaters. Ingot furnace heaters have strict requirements for insulation materials. It must be a material with high temperature resistance, low density, low thermal conductivity, low heat storage, good heat insulation effect, low outgassing, light weight, and small expansion coefficient. Therefore, high-purity graphite is the most ideal among many refractory and thermal insulation materials.

The development value of pure graphite

(1) Speed ​​up the research and development of high-tech products with high added value and high technological content. Most of my country’s current pure graphite products are in the primary mining stage, and they simply use natural resources. Therefore, it is necessary to take protective measures for the exploitation and large-scale operation of pure graphite resources. Accelerate the development of high-tech products with high added value and high technological content. Reasonable use and protection of existing resources.

(2) Make full use of the market to achieve optimal allocation of resources. The rational and orderly flow of products between enterprises is the result of the optimal allocation of resources for the development and utilization of pure graphite. By means of market regulation, the pure graphite market can obtain the best resource allocation through competition and price mechanism.

(3) Strengthen the financial support for the development and utilization of pure graphite. Advanced development and utilization mechanism is an effective means to maximize the benefits of pure graphite resources. The most basic way to realize this development and utilization mechanism is to strengthen financial support. Funds can be set up in the development and utilization of pure graphite purification and new materials to reduce the risk of technological development by enterprises and individuals. For mass products and high-end products with high risk, high investment cost and low income, investment can be increased to ensure the ratio of scientific and technological innovation to income.

At present, many graphite products used in the semiconductor and photovoltaic industries still need to rely heavily on foreign supplies. Demanding in these markets has led to a substantial increase in graphite imports in recent years. This is undoubtedly a good opportunity for the economic development of the graphite industry, and it is also a major opportunity for graphite enterprises to open up new markets. The high-purity graphite powder products for silicon carbide semiconductors developed by our company have fully met the requirements of national standards. They are pioneers in the application of new materials in new fields at home and abroad, and have very strong market competitiveness.