It was noted that ultrasonic vibrations, when introduced into bulk or thin-film semiconductors, stimulated defect reactions. An analysis of such effects was performed here within the framework of a scheme which involved 3-step (release, diffusion, capture) point-defect gettering. When applied to plasma hydrogenated films, the method improved the homogeneity of recombination and transport properties. Ultrasound promoted the passivation of grain boundary defects, as revealed using spatially-resolved photoluminescence, sheet resistance, and atomic force microscopy. The results supported a mechanism which involved trap-limited H diffusion that was facilitated by ultrasound.

Defect Engineering in Polycrystalline Silicon S.Ostapenko: Solid State Phenomena, 1999, 67-68, 485-96