The N concentration distribution C(z) obtained after diffusion of N from the bulk of a sample towards the surface was determined by subsequent heat treatment at moderate temperatures (650C). This process led to the formation of shallow thermal donors (N–O complexes) with a concentration distribution over the depth, z, of the sample that corresponded to the N concentration profile, C(z), and therefore made it possible to calculate this profile. The proposed method was used to determine the N concentration profiles, C(z), after homogenizing annealing at 950, 1000 and 1050C. At high O concentrations, the N transport was promoted by the high-rate dissociation of N dimers. On the other hand, N transport was slightly hindered by the partial oxidation of N monomers. The results indicated that the latter effect was not very strong because the dimeric N species predominated over the monomeric N species in the sample and the diffusion profile was determined by the product, D1K1/2, where D1 was the diffusion coefficient of N monomers and K was the dissociation constant.

Generation of Shallow Nitrogen-Oxygen Donors as a Method for Studying Nitrogen Diffusion in Silicon. V.V.Voronkov, A.V.Batunina, G.I.Voronkova, M.G.Milvidskiĭ: Physics of the Solid State, 2004, 46[7], 1206-12