Stopping and damage parameters for Monte Carlo simulation of MeV implants in crystalline Si

Semiempirical models of electronic energy loss and damage formation for MeV ions (B, P, As) implanted in silicon at room temperature were investigated through the comparison of measurements with Monte Carlo simulations of both impurity and damage depth distributions. Accurate prediction of dopant profiles in an amorphous target and in a low-dose implanted crystal is achieved by a proper parametrization of well known analytic stopping models. Moreover, to accurately describe the dynamic effects of damage accumulation in medium dose implants, a dependence on ion energy of the efficiency parameter used in the Kinchin-Pease (KP) model must be introduced in the simulation. Such a factor, determined by the fit of the measured integral of defect profiles, is found to decrease for P and As ions with increasing the nuclear energy released to primary recoil atoms, apparently reaching a saturation value of about 0.25. Full cascade simulations show that the increasing fraction of the primary recoils energy spent in electronic processes, not considered in the simple KP approximation, cannot explain the observed trend. While the empirical adjustment of damage efficiency leads to a good agreement between simulated and experimental dopant profiles, a systematic underestimate in the depth position of the peaks of simulated damage distributions is observed, which cannot be accounted for by simple ballistic transport effects.