Floating Substrate Process. Large Area Silicon Sheet Task Low-Cost Silicon Solar Array Project. Third Quarterly Progress Report, June 21, 1976--September 24, 1976

摘要

The Seeded Growth Furnace was completed and operated extensively during the third quarter. Optimum thermal geometry, gas flows, and withdrawal rates are being determined. Surface growth was obtained having growth velocity as high as 5 to 6 mm/min. The surface growth has generally taken the form of interlocking crystals and is thin enough to follow the liquid surface. Its thickness has been determined in one case to be 20 microns. A molybdenum susceptor has been made for the seeded growth furnace. It is anticipated that this new design will eliminate the problems caused by films on the melt and seed crystal and lead to improved crystal structure in the silicon growth. A series of experiments were performed in order to determine whether the reactor gas streams were sources of contamination. Nitrogen reacts with silicon at 1100 exp 0 C to coat its surface with a film 30 to 150A thick. Silicon heated in hydrogen at temperatures between 1000 and 1200 exp 0 C maintains a very clean, film-free surface. (ERA citation 02:026071)