Latent accumulation of surface states in MOS structures after exposure to ionizing radiation

A new quantitative model of latent accumulation of surface states in MOS structures after ionizing radiation and prolonged annealing has been developed. The model is based on the formation of H$^+$ hydrogen ions under the influence of ionizing radiation not only in a thin gate dielectric, but also in an adjacent thick field dielectric and its subsequent dispersion transport to the interface with a silicon substrate. The density of latent surface states is determined by the balance equation of passivation and depassivation of $P_b$ -centers on the SiO$_2$–Si interface by hydrogen ions. The model allows us to explain the concomitant drop in the volume charge, as well as the decline in the surface states density after the growth is completed, and satisfactorily describes the experimental data.