Crucibleless crystal zone melting - operating on inductive branch of resonance curve for heating and on capacitive branch for pulling

摘要

In a crucible-less zone melting process for single crystals of a semiconductor such as Si the heating power is supplied by the heating circuit, coupled to a h.g. generator, and consisting of an induction coil and a capacitor in parallel to it. During the heating period of the solid stock, the high-frequency generator operates on the rising inductive branch of the heating circuit resonance curve and during the pulling period from a liquid molten zone on the drooping capacitive branch. Process prevents cracks in the stock during the heating up period and safeguards during pulling against vibrations of the growing single crystal rod. The wattles current is minimised.