APPARATUS AND METHOD FOR GROWING SINGLE CRYSTAL

摘要

PROBLEM TO BE SOLVED: To provide a method for growing a single crystal under gripping the enlarged-diameter portion of the single crystal formed by CZ method, intended to grow and pull it in dislocation-free and stable state without causing its deformation or rupture even if the enlarged-diameter portion stands at high temperatures and the corresponding single crystal rod has a weight of as heavy as about 400 kg with large diameter. SOLUTION: This method for growing a single crystal comprises ensuring the enlarged-diameter portion of the single crystal to be gripped at its high temperatures with heavy weight by controlling the temperature T( deg.C) of the enlarged-diameter portion so as to satisfy the relationship: W<=-(4/3)T+1,270 (W is the weight of the single crystal held under seizure: kg) within the range of the temperature T from 500 to 800 deg.C when the minimum diameter of the neck on the lower part of the enlarged-diameter portion is brought to >=12 mm under the conditions that a site where a gripping member is contacted with the lower part of the enlarged-diameter portion is disposed with a contact member of a material with a surface hardness of >=70 in Shore hardness and <=100 in Vickers hardness and tensile strength of >=400 MPa.