Single crystal growth process for prodn. of silicon single crystal with constant dopant concn. - by melting material in crucible with added impurities, maintaining solid layer and melting from upper portion while drawing

摘要

Process comprises (a) melting single crystal material in a crucible and adding doping impurities; (b) maintaining a solid layer, which solidifies upwardly from the crucible bottom, in co-existence with the overlying molten layer; and (c) melting the solid layer from its upper portion while drawing a single crystal from the molten layer so that single crystal growth occurs with change in the molten layer vol. Solid layer is pref. formed in a certain wt. ratio 'fpo' to the single crystal material at the start of single crystal growth, the single crystal growth operation including a melting the solid layer with a wt. which is a multiple 'alpha' greater than the wt. of the grown single crystal. Value ranges for 'fpo' and 'alpha' and mathematical relationships between 'fpo' and 'alpha' are given. USE/ADVANTAGE - Crystal growth process is used e.g. for growth of P-doped Si single crystals and it suppresses dopant concn. variation in the melt and in the single crystal, giving increased single crystal yield.