METHOD FOR FORMING SHOULDER IN GROWING SILICON SINGLE CRYSTAL

摘要

PROBLEM TO BE SOLVED: To provide a method for forming a shoulder, by which the occurrence of dislocation is suppressed in a step of forming the shoulder and the yield and productivity can be improved when growing a silicon single crystal by CZ method.;SOLUTION: The method comprises changing taper angles from a neck part 9 to a body part 12 in at least two steps (four steps from β₁ to β₄) during growing a silicon single crystal. By carrying out the operation of, at first, keeping the angle of the shoulder part 11 small so as to suppress disturbance and subsequently increasing the angle stepwise to broaden the shoulder part, disturbance in each step can be minimized and the shoulder part can be broadened in a direction of the diameter of a single crystal while the occurrence of dislocation is suppressed. It is preferable to have the larger number of steps of changing taper angles, in order to minimize the disturbance. The method for forming the shoulder is suitably used even for growing a silicon single crystal having a diameter as large as 450 mm. By applying a transverse magnetic field, a silicon single crystal having not only the above effect but no point defect can be grown with high production efficiency.;COPYRIGHT: (C)2010,JPO&INPIT