Role of nitrogen-related complexes in the formation of defects in N-Cz silicon wafers

Defect formation in nitrogen doped Cz silicon (N-Cz Si) has been examined in terms of N-related complex interactions during wafer heat treatments. Defect size distributions were obtained following Hi-Lo-Hi and Lo-Hi cycles as a function of depth using an oxygen precipitate profiler (OPP), while the defects were delineated by Wright etching and Nomarski optical microscopy of both cleaved and bevel polished samples. High Resolution TEM in the near surface region revealed that most precipitates have an octahedral shape and contain two distinct amorphous phases. SIMS depth profiles of N and O were obtained using different sputtering rates to probe both the near-surface and bulk regions. The data indicate a striking correlation of the OPP revealed defects with the N and O profiles. A new mode of oxygen precipitation has been found at the nearsurface which is discussed with regard to N-related complex interactions related to annealing and point defect supersaturations.