Model of Accumulation of Surface States in p-MOS Transistors under Negative Bias

A quantitative model for the accumulation of surface states in p-MOS transistors under negative bias temperature instability (NBTI) is proposed. The model is based on the reaction of hydrogen release from passivated PbH-centers at the interphase boundary of silicon with the gate dielectric under the influence of the field, temperature, and holes of the inversion layer tunneling from the silicon substrate. The kinetics of surface state accumulation at short times is determined by the reaction rate, while at longer times, it is determined by the rate of hydrogen diffusion outflow from the bulk oxide via localized states with a dispersion of binding energies. It is shown that taking into account the dispersion nature of the transfer significantly slows down the process of hydrogen diffusion in an amorphous dielectric. The influence of gate voltage and nitrogen content in the gate insulator on the accumulation of surface states under NBTI is simulated.