REDUCTION OF AIR POCKETS IN SILICON CRYSTALS BY AVOIDING THE INTRODUCTION OF NEARLY INSOLUBLE GASES INTO THE MELT

摘要

A process is provided for controlling the amount of insoluble gas carried by a charge of granular polycrystalline silicon. The process comprises (i) charging a feeding container with granular polycrystalline silicon, (ii) forming an ambient atmosphere in the feeding container, the ambient atmosphere having a mole fraction of at least 0.9 of a gas having a solubility in molten silicon of at least about 5x1013 atoms/cm3 at a temperature near the melting point of silicon and at a pressure of about 1 bar (about 100 kPa), and (iii) reducing the pressure inside the charged feeding container.