Water-Adsorbed States on Silicon and Silicon Oxide Surfaces Analyzed by using Heavy Water

Water-adsorbed states on Si, native oxide and thermal oxide surfaces are investigated by means of thermal desorption spectroscopy. D2O is used to detect the water signals from these surfaces, which are separated from background H2O signals. The water desorption is 1/10 less than the hydrogen desorption. The amount of hydrogen adsorbed is largest on the Si surface and smallest on the thermal oxide surface. Four types of binding states of hydrogen are assigned to be SiO-H and Si-H on the silicon surface, Si-H in the native oxide, and Si-H in the interface between the native oxide and the silicon substrate.