The Study Of Distribution Of Impurity Content In Polycrystalline Silicon Rods

The polycrystalline silicon was an important basis material in solar photovoltaic power industry,the solar-grade polysilicon was universally used for semiconductor materials and integrated circuit substrates,and was extensive applied in aerospace,computer chip and automatic control and other fields.The cost reduction and quality improvement is footed for survival and development of enterprises.Although industry cost of polycrystalline silicon production was reduced though a continual technical transformation,but faces a shock from Europe and the United States market,the persistent technical transformation to quality control of production process was continually explored.The production of Polycrystalline silicon using improved Siemens method was used in present company,the main process is the production of high purity silicon material was obtained core vapor deposition with the trichlorosilane and high purity hydrogen accordance with a certain proportion in the reduction furnace,but in the production process,the different of inherent quality of polysilicon products was existed due to the control and limitations of the process in the same furnace,led to the polysilicon rods used for detected of impurity content of donor and acceptor at different sampling position was different,which led to the judgment of polysilicon grade was difference.The present study was researched the influence the different sampling position on impurity content of donor and acceptor,and to solve the question of discrepancy in the judgment of Grade polysilicon due to uneven impurity distribution.The present study was studied the impurity content of polycrystalline silicon rods in different positions,mainly for the distribution of impurities in different positions of the same furnace(upper,middle and lower part,inner ring,outer ring and middle ring),different locations of the same polysilicon rod(near the skin and near the silicon core)on the same polysilicon rod,different silicon core resistivity at and different silicon core resistivity(45-100?�cm and 100-150?�cm).The results showed the middle and part and middle ring was the representational position in different positions of the same furnace,near the skin within 2mm test bar was choose as the basis for judging the quality of silicon,the relatively large impact was showed on silicon core impurity content on the growth of polysilicon.The disadvantageous influence on product quality was caused by the cleanliness of the replacement process,the migration and diffusion of the impurities under the high temperature condition,the cleanliness of the system in the reduction furnace,and so on.To reduce the influence by certain measures should be reduced though certain measure in order to gradually improve product quality.Simultaneously,the results of the test data were analyzed to find out the influence factors of the impurity content,the corresponding measures,and the verify of improve the operation.The strong basis was provided for different quality distribution products results to the difference of product value bring the quality of lose of enterprise,while identifying the source of pollution for enterprises to improve product quality.