Improvements in the Horizontal Ribbon Growth technique for single crystal silicon

Abstract

An improved Horizontal Ribbon Growth (HRG) technique for growing single crystal ribbons of silicon is described. Starting with the essential concept of the Bleil process, namely the “growth wedge”, improvements were achieved in the process by introducing gas cooling and developing techniques for obtaining a “large wedge factor” (or wedge length to ribbon ratio). These refinements have led to demonstrations of high growth rates (maximum of 415 mm/min for single crystal and 850 mm/min for polycrystal ribbons). Various other improvements in the practice of HRG, such as a specially designed crucible, pulling in an inclined direction, and generation of desired melt flow patterns, are also described. They have led to a more stabilized growth operation from the start of seeding through steady-state growth.