Patent ID: 6416576
Filing Date: 2002-07-09
Classification: C30B

Abstract:
A method for producing a single crystal by growing a semiconductor single crystal from a melt by CZ method, wherein as an index of deformation of the single crystal from a perfect circle, an aimed value dAIM of a crystal deformation defined by (maximum diameterâˆ’minimum diameter)/minimum diameter of a crystal section is previously calculated; an upper limit value VMAX of a pulling rate necessary to suppress a defect density to an allowable range is calculated from distribution of grown-in defects in the crystal section; the single crystal is pulled up in a predetermined pulling rate; then deviation &Dgr;d of an achieved value dACT of the crystal deformation from said aimed value dAIM in pulling is determined, the deviation &Dgr;AIM is converted to a correction &Dgr;V of the pulling rate, this correction &Dgr;V is added to a set value of the pulling rate in said pulling, the pulling rate obtained by this addition is compared with said upper limit value VMAX and the smaller value is selected as the set value of the pulling rate for the following runs.