Effects of Heater and Insulation Ring Designs on Oxygen Content of Large-Diameter Silicon Grown by Czochralski Method

Abstract

Large-diameter monocrystalline silicon wafers with affordable costs dominate the photovoltaic market. Strict control of oxygen content has been proposed to improve quality of silicon wafers and to promote efficiency of solar cells. The aim of this study is to reduce oxygen by analyzing the effect of hot zone structure on oxygen concentration at the crystal-melt interface for 12-inch Czochralski silicon grown from 40-inch quartz crucible. The numerical simulation results show oxygen decreases with elevated heater position related to melt free surface and closer distance between heater and insulation ring. The main reasons are suppression of heat radiation from heater to crucible bottom, and enhancement of thermocapillary convection. With the optimized hot zone structure, lower oxygen content and more uniform axial oxygen distribution can be achieved, which will benefit Cz-Si producers.