GROWTH AND MISFIT ACCOMMODATION OF BETA-SIC PRECIPITATES IN SILICON AS IMPLANTED BY OXYGEN

The fabrication of silicon-on-insulator (SOI) materials by ion beam synthesis is now being successfully employed. The accommodation of B-SiC precipitates was studied by combined plane-view and cross-sectional (XTEM) observations. The mechanism of precipitation during the implantation is commented on. It has been shown that most of the B-SiC precipitates are coherent with the silicon host. Then, the constrained strain around the B-SiC precipitates because of the 4% volume-increase is eliminated by the generation of self-interstitial and vacancy pairs during implantation. The former migrates very fast to the surface, while the latter provides the space for the B-SiC precipitate growth. Such precipitates do not act as sources of dislocations. However, they are responsible for the increase of the dislocation density in SIMOX due to pinning of the dislocation. The dissolution of the precipitates by high temperature annealing, which is successfully applied to SiO2 precipitates, is not applicable to B-SiC precipitates because of their higher stability.