Dispersive transport of hydrogen in MOS structures after exposure to ionizing radiation

It is shown that the description of the dispersive transport of H$^+$ ions, based on the multi-trapping model, allows quantitative description of the kinetics of surface-state formation in metal-oxide-semiconductor (MOS) structures after exposure to ionizing radiation. The time dependences of the density of surface states on the gate dielectric thickness, electric-field strength and polarity are simulated. It is shown that the kinetics of surface-state formation is controlled by the levels of localized states of hydrogen ions in the range from 0.76 to 0.98 eV, the trap concentrations in both the bulk and SiO$_2$ region adjacent to the substrate, and depends on the initial distribution of H$^+$ ions.