CHANNELING IMPLANTATION INTO CHEMICAL-COMPOUNDS

The impact parameter, p, dependence on the electronic stopping power, dE/dx, is discussed, especially concerning the different strength of valence electrons from that of the core ones. The argument is supplemented more clearly by an issue of how the directional effect of ion motion influences the dE/dx in compound crystalline solid. We introduced a rule describing the p-dependent dE/dx of compound crystals, in a different way from Bragg's rule which averages the respective dE/dx of composite atoms according to their stoichiometry. Evaluating the range profiles of ions in binary III-V semiconductors making use of a Monte Carlo simulation, we draw two conclusions: (1) The strength of the p-dependence of dE/dx due to valence electrons, being quite different from that of core electrons, determines the range profiles of implants distinctly. (2) The present rule can be an alternative to Bragg's rule, and available for ions moving with energy smaller than 1 MeV/amu in crystals.