| 摘要 |
#CMT# #/CMT# Depositing (11) polycrystalline silicon on filaments in a deposition reactor by a reaction gas comprising hydrogen and a silicon-containing component, is claimed. The silicon-containing component exhibits a molar saturation of at least 25% with respect to hydrogen. #CMT# : #/CMT# An independent claim is also included for producing polysilicon, comprising (a) carrying out the above mentioned method, (b) supplying exhaust gas obtained from the deposition of the polycrystalline silicon, into a device for cooling the exhaust gas, which includes (i) supplying silicon tetrachloride containing condensed components of the exhaust gas obtained by cooling in the step (b), into a device for distillatively purifying (14) the condensate and (ii) supplying the non-condensed components resulting during cooling, into an adsorption or desorption unit (13), (c) obtaining a first material stream of non-condensing components purified by adsorption, which contains hydrogen, and (d) obtaining a second material stream of non-condensing components during regeneration of the adsorption unit by desorption and purging with a flushing gas, which contains silicon tetrachloride, and supplying the second material stream of non-condensing components to a converter for converting (15) silicon tetrachloride into trichlorosilane. #CMT#USE : #/CMT# The method is useful for depositing polycrystalline silicon on filaments in a deposition reactor. #CMT#ADVANTAGE : #/CMT# The method reduces the concentration of impurities during the deposition cycle, and optimally utilizes and recycles all chlorosilane. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a schematic flow chart of the cyclic process of depositing polycrystalline silicon on filaments in a deposition reactor. 11 : Depositing 12 : Cooling section 13 : Adsorption or desorption 14 : Distilling 15 : Converting #CMT#INORGANIC CHEMISTRY : #/CMT# Preferred Components: The silicon-containing component is trichlorosilane. The temperature during desorption is increased with a rate of less than 0.9 K/minute. Preferred Method: The exhaust gas in the step (b) is cooled at a temperature = -60[deg] C, preferably at a temperature less than the dew point of hydrochloric acid at a corresponding hydrochloric acid content in the exhaust gas and corresponding pressure. The material stream of desorption is examined for the amount of dichlorosilane in the material stream in the step (d), where the material stream is guided to the device for cooling the exhaust gas of the depositing with respect to the step (b), if the percentage of dichlorosilane in the material stream is greater than the amount of the sum of trichlorosilane and silicon tetrachloride, and the material stream is mixed with the exhaust gas obtained during depositing. The method includes obtaining hydrogen from the first material stream in the step (c) as the reaction gas during depositing in the step (a), or as a flushing gas stream during desorption in the step (d), which is purified by adsorption. The molar saturation of the silicon-containing component with respect to hydrogen in the step (a) is at least 30%. #CMT#INSTRUMENTATION AND TESTING : #/CMT# Preferred Components: The converter includes a reactor and a cooling section (12), where the second material stream of desorption obtained in the step (d), is introduced between the reactor and cooling section in the converter, in which the second material stream is mixed with a product gas stream of the conversion, or the second material stream in its gaseous form is directly introduced into a reaction zone of the converter. #CMT#EXAMPLE : #/CMT# No suitable example given. |
