The growth of interstitial agglomerates that formed on {111} and {110} planes during annealing at above 700K, following 200keV electron irradiation, was studied by means of transmission electron microscopy in order to clarify the migration of point defects. Transmission electron microscopic observations showed that the agglomerates formed via 2 processes. One was the introduction of point defects by irradiation, and the other was the migration of point defects during annealing. The nucleation and growth of the agglomerates ceased at an early stage of post-irradiation annealing. The number density of interstitial atoms in the agglomerates, as estimated after the cessation of growth of all of the agglomerates, did not depend upon the annealing temperature but upon the electron dose. It increased quadratically for electron doses of up to 2.5 x 1022/cm2. The results could be explained in terms of a model according to which the agglomerates formed via the migration of Ini-Pi interstitial pairs. These interstitial pairs formed only during electron irradiation, and did not combine with isolated In and P vacancies. The experimental results were consistent with a diffusion model in which the agglomerates formed via migration of the pairs.The migration energy of the pairs was estimated to be 1.52eV.

Diffusion Process of Interstitial Atoms in an Electron Irradiated InP Studied by Transmission Electron Microscopy. Y.Ohno, N.Saitoh, S.Takeda, M.Hirata: Japanese Journal of Applied Physics - 1, 1997, 36[9A], 5628-32