| 摘要 |
A process for producing a single crystal as a multipulling technique in which multiple single crystals (3) are pulled up from raw material melt (4) accommodated in a single crucible within a chamber according to the Czochralski method, comprising pulling single crystal (3) up from raw material melt (4), additionally charging a polycrystalline raw material into the remaining raw material melt (4) and melting the same without cutoff of power for heater (7), pulling subsequent single crystal (3) up, and repeating these to thereby attain pull up of multiple single crystals (3), wherein in order to control for a given value the V/G, referring to the ratio of pull rate (V) exhibited at the growing of cylindrical part of single crystal (3) to crystal temperature gradient (V) exhibited in the direction of pull axis in the vicinity of solid-liquid interface, of each of single crystals (3) pulled up, pull conditions, such as pull rate (V), are amended prior to pulling of single crystal in conformity with the time having elapsed from the initiation of operation to thereby grow single crystals (3) having desired defect regions. Thus, there can be provided a process for producing a single crystal in which a wafer product of desired quality can be produced stably in large quantity at low cost. |
