Failure of the “Kick-Out” Model for the Diffusion of Au into Si when Tested by Monte Carlo Simulation

Abstract

AbstractWe have performed large scale computer simulations on the controversial issue of Au diffusion into Si at T = 1095° C. Using a Monte Carlo algorithm and a conveniently parametrized set of parameters, our computer program is capable of working out the macroscopic consequences of a variety of models, i.e. atom level assumptions, in an unbiased way and without the approximations introduced in analytic calculations.When applied to the “kick-out” hypothesis, our results are dramatically at odds with the properties claimed by its proponents. Neither the profile of the Au substitutionals, nor the Au-interstitial profiles are in agreement with the analytically obtained results. The discrepancy becomes most pronounced when comparing the variation with time of the Au concentration in the center of the sample, which we find to be linear at all times, in contrast to the alleged t1/2 behavior. Moreover, the Au profile of a one-sided diffusion never becomes U-shaped, as experimentally observed.