Investigation of defect structures in multi-crystalline silicon by laser scattering tomography

A variety of defects in multi-crystalline Si has been detected using an in-house made laser scattering tomography tool. Band-to-band photoluminescence excited by the applied LST laser beam is applied for monitoring defect-specific recombination activity. For demonstrating the capability of this setup, defect-rich sections of cast mc-Si and crucible-free grown mc-Si have been investigated. In the former material, LST defects are mostly located close to grain boundaries, impacting their recombination activity. In the latter material, most of LST defects are embedded in low-lifetime grains. The combined LST/PL information allows some conclusions on recombination-controlled quality of mc-Si.