GeH ₄ adsorption on Si(0 0 1) at RT: Transfer of H atoms to Si sites and atomic exchange between Si and Ge

Si(0 0 1) surfaces exposed to various doses of germane (GeH ₄ ) 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 GeH ₄ 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 GeH ₄ molecule adsorption is obtained to be unity at low coverage.