Depth-resolved positron annihilation studies were carried out on nitrogen-implanted Si to investigate defect evolution and thermal stability. Si(100) wafers were implanted with 60keV N+ ions to a fluence of 1 x 1014 and 1 x 1015/cm2. From positron diffusion analysis of defect-sensitive S-parameter profiles, it was found that the higher dose sample undergoes a two-step annealing process consisting of annealing of deep level defects, followed by vacancy agglomeration near the surface at 873K. For the low dose sample, however, nitrogen vacancy complexes were the only major defects remaining at 873K. Annealing at 1073K was sufficient to remove all kinds of open volume defects present in the samples.

Depth Profiling of Vacancy Defects and their Thermal Stability in N-Implanted Si: a Positron Annihilation Study. C.V.Anto, S.Abhaya, P.Magudapathy, G.Amarendra, K.G.M.Nair: Journal of Physics D, 2010, 43[32], 325401