Vacancy out-diffusion in nitrogen-doped silicon

In nitrogen‐doped silicon a strong anneal‐induced resistivity increase was reported – but has remained not fully understood. It is now shown that the complicated evolution of the resistivity depth profiles can be reproduced by a relatively simple model based on the out‐diffusion of vacancies and of nitrogen trimers N3. Both these species are produced by dissociation of VN3 defects that originate from grown‐in neutral vacancy‐nitrogen defects. The major deep donors are attributed to N3 defects. The deduced effective vacancy diffusivity DV at 1000 °C is almost coincident with the value extrapolated from low‐temperature data by Watkins. At 900 °C DV is remarkably smaller due to trapping of vacancies by dimeric nitrogen, N2, that is pronounced at lower T. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)