OXYNITRIDATION-ENHANCED DIFFUSION OF BORON IN LESS-THAN-100-GREATER-THAN SILICON

Diffusion of boron in pure N2, pure NH3, and mixtures of NH3 and N2 ha s been investigated to study the effect of the oxynitridation reaction on the diffusivity. The oxynitridation-enhanced diffusion can be expl ained by a dual mechanism involving both vacancy and interstitial sili con atoms. There is no effect on the enhancement diffusivity due to th e junction depths used here. The interstitial and probably the vacancy concentrations are flat. With a thin SiO2 layer on the silicon wafer and a low boron concentration, the diffusion coefficient can be expres sed as a function of the partial pressure of NH3 and temperature as D = 0.105 exp [-3.22 eV/kT] + 1.0 X 10(-6) exp [-1.71 eV/kT]p(NH3) cm2 s -1