Development of Advanced Methods for Continuous Czochralski Growth. Silicon Sheet Growth Development for the Large Area Silicon Sheet Task of the Low Cost Silicon Solar Array Project. First Quarterly Progress Report, October 4--December 30, 1977

摘要

The overall purpose of this two-stage program is the demonstration of continuous Czochralski growth. In Stage 1, an existing Varian 2850 Czochralski furnace is to be modified for continuous growth by recharging; in Stage 2, a new puller is to be designed and shown capable of producing 100 kg of crystal from the same crucible with an after-grind yield of at least 70%. The three components required to modify the Varian furnace for batch and continuous recharging with granular silicon have been designed and are currently being fabricated. The feasibility of extended growth cycles up to 40 hours long has been demonstrated by a recharge simulation experiment; a 6 inch diameter crystal was pulled from a 20 kg charge, remelted, and pulled again for a total of four growth cycles, 59 exp 1 / sub 8 inch of body length, and approx.65 kg of calculated mass. A preliminary economic analysis indicates that the 1982 SAMICS price goal allocation can be met by sheet production predicated upon the recharging of otherwise standard Czochralski furnaces; the projections are, in 1975 dollars: add-on cost for growth--$37 per m exp 2 , direct poly cost--$46 per m exp 2 , margin available for wafering--$45 per m exp 2 . (ERA citation 03:049779)