An experiment was proposed in which impurity diffusion in a semiconductor layer during heat treatment could be controlled by a non-linear potential produced by split gates. The non-linear potential was approximated by a parabola which was centered at the middle of the semiconductor layer; the impurities diffuse into the central region. Starting with the phenomenological Arrhenius equation, a simple model was described for the impurity diffusion, and then perform Monte Carlo simulations to predict the impurity profile, for different parabolic constants and impurity densities. The results showed that charge builds up in the central area creating a long-range internal electric field. The internal field at high doping levels, could be of sufficient strength to cause the broadening of the impurity density profile. The width of the impurity profile could be controlled by the curvature of the parabola, which in turn depends on the split-gate geometry and voltage.

Monte Carlo Simulation of Controlled Impurity Diffusion in Semiconductors using Split Gates. V.Narayan, M.Willander: Physical Review B, 2002, 65[7], 075308 (5pp)