Surface reconstruction of Si(100) and the effect of hydrogen absorption

A detailed LEED study of the clean Si(100)(2*1) surface and the effects of hydrogen adsorption has been made. Adsorption of hydrogen in the presence of a hot filament modifies the structure to give a sharp (1*1) LEED pattern, and the intensity data are consistent with the structure of the silicon atoms being in the bulk structure sites. This observation is in conflict with the only previously reported study of hydrogen adsorption using LEED, and favours certain models for the (2*1) reconstructed surface which have recently been discarded as incompatible with the earlier experimental result of Ibach and Rowe (1974).