Diffusion of phosphorus in silicon in an ambient of pure N2, pure NH3 and mixtures of NH3 and N2 was investigated in order to study the effect of the direct nitridation reaction upon the diffusivity. The diffusion coefficient of P could be expressed as a function of the partial pressure of NH3 and temperature as:

D(cm2/s) = 0.145 exp[-3.26(eV)/kT]-1.26 x 102 exp[-4.11(eV)/kT]PNH3

N.K.Chen, C.Lee: Journal of the Electrochemical Society, 1996, 143[1], 352-5