PROCESS FOR PRODUCING SINGLE CRYSTAL, FLOW REGULATION TUBE AND SINGLE CRYSTAL PULLING APPARATUS

摘要

In the production of a single crystal (6) with the use of a single crystal pulling apparatus (1A), during the pre-growth period after addition, the intra-tube pressure of a flow regulation tube (35A) is controlled at 33,331 to 79,993 Pa and the flow rate of inert gas within the flow regulation tube (35A) is controlled at 0.06 to 0.31 m/sec (0.005 to 0.056 SL/min?cm2). Because of the control of the flow rate of inert gas during the pre-growth period after addition at the above value, even under conditions such that the intra-tube pressure is set to the above relatively high value, the flow of inert gas can be smooth and any evaporation of volatile dopant attributed to the back flow of inert gas can be inhibited. Therefore, there can be attained inhibition of sticking of the volatile dopant in amorphous form to the interior of the flow regulation tube (35A) leading to fixing or dropping during the crystal growth, inhibition of lowering of the ratio of conversion to single crystal and facilitation of removal of sticking matter.