polysilicon has a gray metallic luster and a density of 2.32~2.34g/cm3. Melting point 1410℃. Boiling point 2355℃. Soluble in a mixture of hydrofluoric acid and nitric acid, insoluble in water, nitric acid and hydrochloric acid. Its hardness is between that of germanium and quartz. It is brittle at room temperature and easily breaks when cut. It becomes ductile when heated to above 800℃, and shows obvious deformation at 1300℃. It is inactive at room temperature and reacts with oxygen, nitrogen, sulfur, etc. at high temperatures. In a high-temperature molten state, it has great chemical activity and can react with almost any material. It has semiconductor properties and is an extremely important and excellent semiconductor material, but trace amounts of impurities can greatly affect its conductivity. It is widely used in the electronics industry as a basic material for manufacturing semiconductor radios, tape recorders, refrigerators, color TVs, video recorders, and electronic computers. It is obtained by chlorinating dry silicon powder and dry hydrogen chloride gas under certain conditions, and then condensing, distilling, and reducing.
polysilicon can be used as the raw material for pulling single crystal silicon. The difference between polysilicon and single crystal silicon is mainly manifested in physical properties. For example, the anisotropy of mechanical properties, optical properties and thermal properties is far less obvious than that of single crystal silicon; in terms of electrical properties, the conductivity of polysilicon crystals is also far less significant than that of single crystal silicon, and even has almost no conductivity. In terms of chemical activity, the difference between the two is very small. polysilicon and single crystal silicon can be distinguished from each other in appearance, but the real identification must be determined by analyzing the crystal plane direction, conductivity type and resistivity of the crystal. polysilicon is the direct raw material for the production of single crystal silicon, and is the basic electronic information material for contemporary semiconductor devices such as artificial intelligence, automatic control, information processing, and photoelectric conversion.
Post time: Oct-21-2024
