Depth profiling of defects in nitrogen implanted silicon using a slow positron beam

Positron annihilation spectroscopy (PAS) has been used to determine the subsurface vacancy profile in Si after implantation with 50 keV nitrogen ions for a range of fluences from 5×1011 to 1×1014 cm−2. The spatial extent of the defect distributions was estimated by employing composite-Gaussian defect profiles in the ROYPROF positron diffusion analysis program. The results are compared with both VEPFIT and TRIM (TRansport of Ions in Matter) calculations.