Photo-excitation with light (60mW/cm2) at the same time as B implantation (30keV, 2 x 1015/cm2), changed the density and the dimensions of radiation defects. Rapid annealing (1100C, 10s) led to the formation of dislocation loops in samples which had been implanted in the normal manner. The heating effect which was due to the illumination amounted to less than 15C. The non-irradiated surfaces of the samples were chemically etched and their microstructures were investigated by means of transmission electron microscopy. There was a difference in the structures of light and dark as-implanted samples; the former contained more finely dispersed defects. It was clear that the defect concentration in both cases was also different. Post-implantation annealing caused a marked difference in the structures of irradiated material. In the case of dark-implanted material, heat treatment produced interstitial dislocation loops with a Burgers vector of a/2<110>. In the case of light-implanted samples, dislocation loops were absent after annealing, and there were only a large number of micro-defects whose nature was not well-established. It was possible that they were clusters of interstitial atoms. The preliminary results of X-ray diffraction investigations showed that, in light-implanted samples after annealing, stretching of the crystal lattice could be detected in irradiated layers as compared with dark-implanted layers. It was assumed that the concentration of interstitial-type defects in light-implanted material after heat-treatment was higher than in dark-implanted samples. It was emphasized that an additional ionization of Si atoms during implantation affected not only the concentration and distribution of radiation defects, but also markedly affected their nature.

J.N.Erokhin, A.G.Italyantsev, A.A.Malinin, V.N.Mordkovich: Radiation Effects and Defects in Solids, 1994, 128[3], 187-8