Residual Stresses

This paper summarizes the research on the characterization of residual stresses and lifetime of polycrystalline sheet silicon for photovoltaic application. Full-field polariscopy, scanning room temperature photoluminescence (PL) and surface photovoltage (SPV) are used to characterize unprocessed silicon sheets. An orientation-dependent stress-optic coefficient has been developed and used to extract the in-plane residual stresses. The characteristics of the spatial distribution and the quantitative correlation between the residual stresses and the lifetime are presented.