Potential sputtering of proton from hydrogen-terminated Si(100) surfaces induced with slow highly charged ions

A potential sputtering mechanism of hydrogen has been studied for impact of slow highly charged Xeq+ ions (<5 keV, q=4-12) on well-defined H-terminated Si(100) surfaces. It was found that the sputtering yields of protons are proportional to q(γ) (γ∼5), independent of the surface condition, that is, for both Si(100)2x1-H surface and Si(100)1x1-H surface. The yield for Si(100)1x1-H surface was ten times larger than that for Si(100)2x1-H surface, although the H coverage of the former is only twice the latter. Surface roughness is found to be the key parameter to vary the yield, and also to influence the energy distribution of sputtered protons. These findings are consistently explained with a pair-wise bond-breaking model induced by a double electron capture, where the classical over barrier process plays an essential role. (C) 2002 American Institute of Physics.