SILICON INGOT CASTING - HEAT EXCHANGER METHOD MULTI-WIRE SLICING - FIXED ABRASIVE SLICING TECHNIQUE (PHASE III) Silicon Sheet Growth Development for the Large Area Sheet Task of the Low-Cost Solar Array Project Quarterly Progress Report No. 3

摘要

Ingot casting has been scaled up to 16 cm x 16 cm square cross-section size weighing up to 8.1 kg. The high degree of crystallinity has been maintained in the large ingot. For large sizes, the non-uniformity of heat treatment causes "chipping" of the surface of the ingot. Significant effort and progress has been made in the development of a uniform graded structure in the silica crucibles.nThe high speed slicer has been modified so that the blade-head weight is reduced to 37 pounds. This has allowed higher surface speeds of up to 500 feet per minute. Slicing of 10 cm diameter workpieces at these speeds has increased the through¬put of the machine to 5.7 mils/min., 0.145 mm/min., 50 per cent more than the projected cutting rates used in the economic analysis.