Ripple structures on ion bombarded surfaces arising from the sputter yield dependence on incidence angle

Abstract

It is shown that ripple structures on oblique incidence ion bombarded surfaces can be stable features under ion erosion without the necessity to invoke mass redistribution, surface diffusion or micro-roughening due to surface curvature dependent energy deposition. Instead the patterns are predicted to be a natural consequence of non-linear effects due to the dependence of the sputtering yield on the angle of incidence.

Surface morphology of tungsten exposed to helium plasma at temperatures below fuzz formation threshold 1073 K

“…There are several possibilities to explain the formation mechanism by analogy with other studies, e.g. crystal orientation dependence of slip [23], sputtering [26] and combined effect of the sputtering and surface diffusion [27,28]. However, since the undulating surface structures frequently have a jagged edge, the slipping effect is considered unlikely.…”

“…These surface structures also have variations among grains, and it is reasonable to expect that the crystal orientation has an impact on the surface modifications in the wide temperature range. There are few possibilities to explain the formation mechanism by the analogy with other studies, e.g., crystal orientation dependence of slip [23], sputtering [26] and combined effect of the sputtering and surface diffusion [27,28]. However, since the undulating surface structure frequently have a jagged edge, the slipping effect is considered unlikely.…”