A study was made of the effect of the annealing ambient upon the behavior of Er impurity atoms which had been introduced into Czochralski-type material by diffusion from a surface source. Silicon nitride films which partially covered the surface of test structures were used to prevent any effect of the annealing atmosphere upon 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 beneath the uncovered surfaces than beneath nitride-covered surfaces. However, after annealing in an oxidizing atmosphere the depth and the concentration were smaller beneath the uncovered surface. The results were explained in terms of excess intrinsic point defects which were generated during annealing and interacted with electrically active and inactive Er atoms.

O.V.Alexandrov, N.A.Sobolev, E.I.Shek: Semiconductor Science and Technology, 1995, 10[7], 948-51