Hydrogen-Induced Valence Alternation State atSiO2Interfaces

Exposure of $\mathrm{Si}/{\mathrm{SiO}}_2$ and $\mathrm{SiC}/{\mathrm{SiO}}_2$ interfaces to hydrogen in the temperature range of $450–800°\mathrm{C}$ is found to produce a considerable density (up to ${10}^{13}\mathrm{cm}{}^{-2\mathrm{}}$) of positively charged centers. The absence of any correlation between the charging process and the presence of Si dangling bond centers in ${\mathrm{SiO}}_2$ or at the $\mathrm{Si}/{\mathrm{SiO}}_2$ interface indicates hydrogen bonding in a valence alternation state which is suggested to be an over-coordinated oxygen center $[{\mathrm{Si}}_2=\mathrm{OH}{]}^{+}$ stabilized by ${\mathrm{SiO}}_2$ network rearrangement at the interface.