Apparatus and method for producing single crystals

摘要

The present invention provides an apparatus for producing single crystals according to the Czochralski method, the apparatus including a chamber that can be divided into a plurality of chambers; at least one of the plurality of divided chambers having a circulating coolant passage in which a circulating coolant for cooling the chamber circulates; and measuring means that respectively measure an inlet temperature, an outlet temperature, and a circulating coolant flow rate of the circulating coolant in the circulating coolant passage; the apparatus further including a calculating means that calculates a quantity of heat removed from the chamber and/or a proportion of the quantity of removed heat, from the measured values of the inlet temperature, outlet temperature, and circulating coolant flow rate; and a pulling rate control means that controls a pulling rate of the single crystal based on the resulting quantity of removed heat and/or the resulting proportion of the quantity of removed heat. The invention also provides a method for producing single crystals using the apparatus. Thus, an apparatus and a method for producing single crystals are provided for producing single crystals while easily stabilizing the crystal quality.

主权项

1. A method for producing single crystals according to a Czochralski method, at least, using an apparatus for producing single crystals comprising a chamber that can be divided into a plurality of chambers, the method comprising:
a first step of calculating a quantity of heat removed from at least one of a plurality of divided chambers by cooling with a circulating coolant and/or a proportion of the quantity of removed heat; a second step of investigating a relationship between a variation in the quantity of removed heat from the chamber and/or the proportion of the quantity of removed heat and a crystal quality associated with aggregation defects of the resulting single crystal; a third step of determining a relationship between a quantity of removed heat from a chamber and/or a proportion of the quantity of removed heat and a single-crystal pulling rate that produces a desired crystal quality associated with aggregation defects, with respect to a target chamber having a correlation between a variation in the quantity of removed heat from the chamber and/or the proportion of the quantity of removed heat and a change in the crystal quality associated with aggregation defects of the resulting single crystal; a fourth step of correcting a set value of single-crystal pulling rate so as to give a pulling rate that produces a desired crystal quality associated with aggregation defects, based on the quantity of removed heat from the target chamber and/or the proportion of the quantity of removed heat; and a fifth step of pulling a single crystal from a crucible at the corrected single-crystal pulling rate, wherein the quantity of heat removed from the at least one of the plurality of divided chambers by cooling with the circulating coolant, and/or the proportion of the quantity of removed heat, is calculated from measured values of an inlet temperature, an outlet temperature and a circulating coolant flow rate of the circulating coolant in a circulating coolant passage.