Low-energy (15 to 50eV) noble gas ion bombardment at low temperatures (less than 300C) led to the formation of a Si(001) 2 x 1 surface reconstruction that was H-terminated by a HF dip before irradiation. By using 19eV He+ bombardment, a (2 x 1) reconstruction could be formed at temperatures which were as low as 50C. This was the lowest temperature that had ever been reported for the formation of this reconstruction. The (2 x 1) reconstruction occurred as a result of surface H removal by sputtering and recoil implantation into the Si substrate. Molecular dynamics simulations of the low-energy irradiation of a H-terminated Si surface indicated that chemically-enhanced physical sputtering of Si occurred in addition to the physical sputtering of H. The H sputtering yield was found to depend strongly upon the H surface coverage. The results suggested that low-energy ion irradiation could be used to tailor the H coverage and, thereby, the chemical reactivity of the Si surface.

M.V.R.Murty, H.A.Atwater: Nuclear Instruments and Methods in Physics Research B, 1995, 102[1-4], 293-300