EFFECT OF POLISHING ON TIME-DEPENDENCE OF AVERAGE SUBSTITUTIONAL IMPURITY CONCENTRATION IN DISSOCIATIVE AND KICK-OUT MECHANISMS

From the standpoint of experimentally distinguishing the dissociative mechanism from the kick-out mechanism, the time dependence of the substitutional impurity concentration in the diffusion is useful. In a dislocation-free sample, the reaction of point defects with sample surfaces is the limiting process, and the impurity concentration may depend on distance from the surface. In the experiment, the surface is polished before the concentration measurement. Therefore it is important to know the effect of amount of polishing on the time dependence of the average substitutional impurity concentration. In this paper, the effects for both in-diffusion and annealing processes are calculated. It is concluded that, when a dislocation-free sample is used, the effect is strong for both in-diffusion and annealing processes in terms of the dissociative mechanism and for the annealing process in terms of the kick-out mechanism.