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Title: LSSA Large Area Silicon Sheet Task: continuous Czochralski process development. Quarterly report No. 2, January--March 1978. Texas Instruments report No. 03-78-11

Technical Report ·
DOI:https://doi.org/10.2172/6808679· OSTI ID:6808679

A commercial puller having a 12-kg main crucible capacity is being modified extensively to permit installation of an auxiliary crucible with attendant silicon storage and feed system. The various puller modifications have been designed and are currently being fabricated. All major externally purchased parts such as a metallurgical vacuum valve, auxiliary power supply, and silicon feed system are on order. Puller assembly and checkout will be accomplished during the second quarter of this year. Several experiments have been run in existing equipment examining suitable configurations of auxiliary melters. Heating of the auxiliary melt can be accomplished fairly easily using graphite resistance heaters. Power inputs around 4.5 kVA have proven sufficient to maintain 700 g melts. A major problem uncovered in these experiments is getting the molten silicon to flow properly from the quartz crucibles. Also, thin quartz crucibles tend to devitrify excessively, limiting the run time. These problems can be circumvented by using SiC-coated graphite crucibles, but primary melt contamination may be a problem with graphite crucibles. Economics of a continuous Czochralski process with 100 kg furnace runs of 10-cm diameter crystal indicate a crystal cost in the $24.00/m/sup 2/ range exclusive of polysilicon and slicing costs.

Research Organization:
Texas Instruments, Inc., Dallas, TX (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
NAS-7-100-954887
OSTI ID:
6808679
Report Number(s):
DOE/JPL/954887-2
Country of Publication:
United States
Language:
English