Latent Accumulation of Surface States in MOS Structures after Exposure to Ionizing Radiation

Abstract

A new quantitative model of the latent accumulation of surface states in metal–oxide–semiconductor (MOS) structures after exposure to ionizing radiation and prolonged annealing is developed. The model is based on the formation of H⁺ hydrogen ions under exposure to ionizing radiation not only in a thin gate dielectric, but also in an adjacent thick field dielectric, and their subsequent dispersive transport to the interface with a silicon substrate. The density of latent surface states is defined by the Р_b center passivation–depassivation balance equation at the SiO₂–Si interface by hydrogen ions. The model allows us to explain the concomitant drop in the volume charge, as well as the decrease in the density of surface states (SS) after growth completion, and satisfactorily describes the experimental data.