The migration of P under ambients of pure N2, pure NH3, or their mixtures, was investigated in order to determine the effect of oxynitridation reactions upon diffusivity. In the presence of a thin SiO2 layer on the Si wafer, and a low P concentration, the diffusivity of P could be described by:

D(cm2/s) = 0.145 exp[-3.26(eV)/kT] + 1.718 x 10-6 exp[-1.72(eV)/kT]PNH3

The ratio of the interstitial concentration under oxynitridation conditions, to that under inert conditions, could be described by:

R = 1 + 0.00001183 exp[1.54(eV)/kT]PNH3

By applying the present results to published data, the fraction of B diffusion which occurred via an interstitial mechanism was estimated to be 0.88.

Oxynitridation-Enhanced Diffusion of Phosphorus in <100> Silicon. N.K.Chen, C.Lee: Journal of the Electrochemical Society, 1995, 142[6], 2051-4