Detection and analysis of crystal defects in silicon by scanning infrared depolarization and photoluminescence heterodyne techniques

The coupling of photoelasticity and photoluminescence measurement techniques represents a powerful tool for non-destructive defect monitoring in silicon wafers. By rapid scanning the infrared depolarization (SIRD) allows the detection of crystal defects in 300-mm wafers in a process related time scale of 3 min by full wafer imaging of the local crystal distortions. Coordinate transfer and local investigation by photoluminescence heterodyne reveal the change of the electrical properties of the wafer due to the crystal defects. Crystal defects such as sliplines, boat marks or support related glide bands are investigated after repeated high temperature processing. The defects are caused by local temperature gradients and possess a potential influence for degradation in subsequent thermal treatment.