Si(0 0 1) surfaces exposed to various doses of germane (GeH4) at room temperature (RT) have been investigated by using temperature-programmed desorption (TPD) and multiple internal reflection Fourier transform infrared spectroscopy (MIR-FTIR). It is found that all H atoms from GeH4 molecules are transferred to surface Si atoms on adsorption, and form mainly doubly occupied Si dimers. Ge hydrides and Si higher hydrides rarely exist. These features persist beyond 1 monolayer of the hydrogen coverage. These findings strongly suggest atomic exchange between Ge adatoms and surface Si atoms even at RT. Through analysis of H uptake curve, the number of necessary surface dangling bonds for a GeH4 molecule adsorption is obtained to be unity at low coverage. (C) 2003 Elsevier B.V. All rights reserved.