Penetration of Hydrogen and Deuterium into Si and Hydrogen States in Si

We review recent works on 1) an isotope effect of penetration of Hydrogen(H) and Deuterium(D) into Silicon through Si/SiO2 interface and 2) H effects for Si nanostructures, as well as summary of hydrogen states in crystal Si. In particular, a new filtering effect of H and D isotope atoms was found for penetration process into crystal silicon (Si) through the interface between a Si and SiO2 native oxide layer. More H atoms are introduced into Si than D for mixing gases. This phenomenon can be tentatively explained in terms of an isotope filtering model of H and D via an intermediate cluster state formed at the interface between the native SiO2 layer and crystal Si. Hydrogen passivation of interface defects is shown to be needed for knowing proper impurity doping effects, and electronic, optical, and magnetic properties in Si nanostructures.