Continuous Czochralski growth: silicon sheet growth development of the large area silicon sheets task of the Low Cost Silicon Solar Array Project. Ninth quarterly progress report, October 1-December 31, 1979

During this reporting period, four more 100 kg continuous runs were completed to satisfy the six required by the project extension. One of the four (2*) was performed using a new standard CG2000 RC grower, using accessory equipment and process techniques developed under this project. The sixth and final 100 kg continuous run was performed with purified carbon parts and resulted in the best results to date. Run No. 62 resulted in 103.0 kg being pulled from 104.5 kg total charge weight (98.6% pulled yield). Of this 103 kg grown, 89.3 kg were monocrystalline. Moreover, 72.2 kg was OD material. Another encouraging result was that 85% of the eighth crystal was monocrystalline and 67% of the ninth and last crystal was monocrystaline after ninety seven hours of continuous growth. Impurity analysis data indicate that impurity build-up in grown crystals during 100 kg continuous runs is insignificant. However, the results indicate that impurities tend to accumulate in the crucible. Moreover, impurity analysis performed on new crucibles indicates that these new crucibles may not be as pure as the manufacturer's literature states. Solar cell efficiency data from two 100 kg continuous runs were received this quarter with very encouraging results. The average efficiencies of all cells tested was 16.35% AM1, which is considerably higher than our 14% AM1 goal. Moreover, the efficiencies remained at or near the same levels throughout the entire 100 kg continuous run. We expect to receive solar cell efficiency results from three more of the 100 kg continuous runs in the next quarter