EFFECT OF EXCESS INTRINSIC POINT-DEFECTS ON ERBIUM DIFFUSION IN SILICON

We have studied the effect of the annealing atmosphere on the behaviour of Er impurity atoms introduced in Czochralski-grown Si by means of diffusion from a surface source. Silicon nitride films partially covering the surface of test structures were used to prevent any effect of the annealing atmosphere on Er diffusion. After annealing in an inert atmosphere, the penetration depth and the concentration of electrically active Er impurity atoms were found to be larger under the uncovered silicon surface than the values under the surface covered with a nitride layer. By contrast, after annealing in an oxidizing atmosphere, the depth and the concentration were lower under the uncovered surface. The results have been accounted for by excess intrinsic point defects being generated during annealing and interacting with electrically active and inactive Er impurity atoms.