Computer simulation study on incident fluence dependence of ion reflection and sputtering processes from layered and mixed materials

The fluence dependence of D ion reflection and sputtering from C-layered W material, W-layered C material and WxC1-x mixed material, has been demonstrated using the dynamic Monte Carlo program, EDDY. The fluence-dependent depth profile distributions explain such fluence dependence. For the layered materials, the fluence variations of reflection and sputtering are dependent on layer thickness. In particular, for the C layer thickness parallel to the mean ion range for the impact to pure C, the sputtering of the C layer is enhanced with increasing fluence by C emission due to the reflective scattering collisions of D with W near the surface. This is essentially due to the large target mass difference between W and C, which also brings about the fluence variations for the mixed material. The C sputtering is suppressed due to the dynamic behavior of C in the mixed material, whereas the reflection and W sputtering are enhanced. (author)