Low-Cost Solar-Array Project: Cell and Module Formation Research Area. Process Research of Non-CZ Silicon Material. Quarterly Report No. 1, February 10, 1982 to May 31, 1982

摘要

Technical work in this time period was focused on investigations of liquid applied dopants to replace the gaseous diffusion operations specified for forming back and front junctions in the Westinghouse baseline process sequence for producing solar cells from dendritic web silicon. The use of liquid dopants as an alternate to gaseous diffusion could improve the cost effectiveness of the baseline process sequence by using less expensive chemicals and equipment, less involved procedures, simplified controls, and by eliminating several cleaning steps. Cells manufactured using liquid applied boron have cell efficiencies equally as high as those of the baseline gaseous diffusion operation. A diffusion mask is required to protect the front (sun side) surface of cells during liquid boron diffusion. Glass formed during diffusion of liquid phosphorus applied with a meniscus coater can be readily removed with the standard oxide removal step of the baseline process sequence. Cell efficiencies at least as high as 13.3% have been achieved with liquid phosphorus diffused cells. In addition, experiments were conducted this quarter using a liquid applied diffusion mask to replace chemically vapor deposited SiO sub 2 . The results have shown that previously reported post-diffusion oxide removal difficulties can be eliminated by diffusion in an O sub 2 environment. (ERA citation 07:042788)