The microstructure and minority carrier lifetime of silicon were investigated in uniaxially compressed silicon samples. The objective of the investigation was to determine if it is feasible to produce silicon solar cells from sheet formed by high temperature deformation. The initial structure of the silicon samples ranged from single crystal to fine grained polycrystals. The samples had been deformed at strain-rates of 0.1 to 8.5 s-1 and temperatures of 1270 to 1380°C. Recrystallization was incomplete even after long anneals. A 10 h anneal of fine grained samples with as much as 51 pct strain only caused 95 pct of the samples to recrystallize and even then the recrystallized grains contained twin boundaries and dislocations. The recrystallization in the large grained material was also incomplete and further, it has been shown that large grained material cracks readily during significant deformation (>40 pct). The major mode of recrystallization appears to be migration of existing boundaries into the deformed regions. Minority carrier diffusion length was found to be drastically reduced after deformation, perhaps due to contamination or cooling rate, and recovered only slightly with annealing. These results suggest that high temperature deformation, of silicon to directly produce sheet for solar cells of high efficiency is not practical. Potential may exist for its use as a coarse grained substrate. © 1979 American Society for Metals and the Metallurgical Society of AIME.
