AUXILIARY APPARATUS FOR MELTING SINGLE CRYSTAL RAW MATERIAL AND MELTING OF SINGLE CRYSTAL RAW MATERIAL IN AUXILIARY APPARATUS FOR MELTING SINGLE CRYSTAL RAW MATERIAL

摘要

PROBLEM TO BE SOLVED: To shorten the melting time by improving the thermal efficiency when heating and melting a raw material in an auxiliary crucible according to an induction heating method. ;SOLUTION: Since a secondary induction current is readily gathered on the surface of an electric conductor and the tendency is strengthened with increasing frequency, the thickness of an electroconductive susceptor 2 and the frequency applied to a high-frequency coil 3 are selected so that the thickness of the electroconductive susceptor 2 is decreased from the permeation depth of the secondary induction current. If a high-frequency current is applied to the high-frequency coil 3 when the electroconductivity of the raw material is relatively small, the secondary induction current is generated in the electroconductive susceptor 2 to generate Joule's heat in the electroconductive susceptor 2 by the secondary induction current. The heat of the electroconductive susceptor 2 is transmitted through an auxiliary crucible 1 to the raw material in the interior thereof to heat the raw material. An electric power at a relatively low frequency is applied when the raw material is at a low temperature and the electroconductivity is relatively small. Furthermore, an electric power at a relatively high frequency is applied when the raw material is at a high temperature and the electroconductivity is relatively large.;COPYRIGHT: (C)1999,JPO