Two-Crucible Czochralski Process

Abstract

Scheme for continuous melt replenishment increases capacity of Czochralski crystal-growing furnace. Replenishing and drawing crucibles of improved Czochralski apparatus connected by heated quartz siphon. When doped silicon added to replenishing crucible, liquid silicon flows into drawing crucible, equalizing two melt levels. Addition of new material automatically controlled in response to optically sensed melt level. Results of this semicontinuous operation higher production speed, lower cost, and good control of crystal quality.