Reduction device and process for efficiently producing polycrystalline silicon

Abstract

The invention discloses a reduction device and a process for efficiently producing polycrystalline silicon. The device comprises a material mixing system, a material vaporization system, and a systemfor reducing chlorosilane to form polycrystalline siliconpolysilicon, wherein the material mixing system comprises a trichlorosilane feed regulating valve, a dichlorosilane feed regulating valve and amaterial mixer; the ratio of dichlorosilane is adjusted at different stages in a reduction process. The vaporization system uses 1 MPa of steam as a heat source to vaporize the dichlorosilane, trichlorosilane and hydrogen into 0.9-1 MPa of mixed gas. The polycrystalline siliconpolysilicon generation system mainly refers to a chemical vapor deposition (CVD) reduction furnace, and the CVD reductionfurnace mainly consists of two parts, i.e., a chassis and a furnace cylinder, wherein electrodes, feed spray nozzles and a gas outlet are distributed on the chassis of the reduction furnace, and thearrangement of the spray nozzles can be adjusted. By means of optimization of the spray nozzles, the ratio of the dichlorosilane, the amount of materials, the current increase amount and the like areadjusted at the different stages of the reduction process, so that the deposition rate of silicon is increased under the premise of guaranteeing stable operation of the reduction process, and the purpose of reducing power consumption is achieved.

Description

technical field [0001] The invention belongs to the field of polysilicon production, in particular to a reduction device and process for efficiently producing polysilicon. Background technique [0002] The industrialization of polysilicon in my country began in the 1950s and developed rapidly in the early 21st century. With technological innovation and technological progress, the competition in the polysilicon industry has intensified. How to reduce the production cost of polysilicon and improve the production efficiency of polysilicon is based on polysilicon key to the industry. [0003] The reduction process is the most important link in the polysilicon production process. The core equipment of this process is the CVD reduction furnace. This type of furnace has high requirements on the control of the temperature field and flow field during the polysilicon deposition process, and it is necessary to ensure the uniformity of the polysilicon deposition process. Otherwise, situ...

AI Technical Summary

Problems solved by technology

Later, it was found that a small amount of dichlorodihydrosilane contained in trichlorosilane can promote the reduction reaction, and because the activity of dichlorodihydrosilane is higher, the reduction reaction can be carried out faster, and the energy consumed less; however, if the content of dichlorodihydrosilane is too high, when the space temperature in the furnace reaches a certain level, the silicon produced by reduction will not deposit on the surface of the silicon rod, but will react in the space and float in the furnace , forming amorphous silicon, which is in the form of powder, and will enter the next process through the exhaust port, and circulate infinitely in the entire large system. When a certain amount is accumulated, it will cause a series of problems such as pipeline blockage and worn valves. question

Images