Development of a polysilicon process based on chemical vapor deposition of dichlorosilane in an advanced Siemen's reactor

Dichlorosilane (DCS) was used as the feedstock for an advanced decomposition reactor for silicon production. The advanced reactor had a cool bell jar wall temperature, 300(0)C. The cooler wall temperature allows DCS flow rates and concentrations. A silicon deposition rate of 2.28 gm/hr cm was achieved with power consumption of 59 kWh/kg. It is suggested that a 2.8 gm/hr cm deposition rate is possible. The 2.8 gm/hr cm deposition rate surpasses the goal of 2.0 gm/hr cm. Power consumption and conversion should approach the program goals of 60 kWh/kg and 40%. Stainless steel, Hastalloy B, Monel 400 and 1010-1020 carbon steel were placed individually in an experimental scale reactor. Silicon was deposited from trichlorosilane feedstock. The resultant silicon was analyzed for electrically active and metallic impurities and carbon. No material contributed significant amounts of electrically active or metallic impurities, but all contributed carbon. Single crystal growth was not maintained in most zone refining evaluations. Most materials are considered for use in construction of decomposition reactor components for production of photovoltaic grade silicon; however, further evaluation and the use of the low carbon alloys is recommended.