Scanning photoluminescence for wafer characterization

A new non-contact technique (SiPHER) has been developed to characterize the near-surface region of bulk Si and epilayers. The technique is based on luminescence and can be used to record whole wafer maps (up to 300mm diameter) and also micro maps (1 mu m data sampling). Comparison with EBIC measurements shows that defects with shallow recombination levels can be readily detected at room temperature without sample cooling. The near surface sensitivity of the technique is confirmed with direct cross-correlation with TEM measurements. Epilayer wafers that have been contaminated prior to or during epilayer were analysed. Defects produced due to contamination during surface cleaning were detected around the periphery of the epilayer correlating with preferential defect etching measurements. Whole wafer maps of epilayers that were found to have been contaminated during growth, show distinctive spatial non-uniformity's reflecting the distribution of impurities.