A first order diffusion approximation to atomic redistribution during ion bombardment of solids, II. finite range approximation

An improved diffusion approximation, in which diffusion enhancement operates only over a finite depth, to model atomic redistribution resulting from recoil and cascade mixing during ion bombardment of solids is described, it is shown that this model correctly simulates the main results of the more complex linear cascade atomic collision calculations of positive mean depth shifts, negative peak shifts, broadenings and exponential tails in surface concentration of diffusant marker species during sputter erosion. The analytic method of generalisation to any arbitrary and more realistic diffusivity-depth profiles is also outlined.