A drift-diffusion-based analytic description of the energy distribution function for hot-carrier degradation in decananometer nMOSFETs

Abstract

We extend our drift-diffusion based model for the carrier energy distribution function (DF), which was derived to describe hot-carrier degradation in LDMOS transistors, for the case of decananometer nMOSFETs with a gate length of 65 nm. This approach is based on an analytical expression for the DF with parameters obtained from the drift-diffusion model. To approximately consider the important effect of electron-electron scattering on the shape of the distribution function, we solve the balance equation for the in- and out-scattering rates. We compare the DFs obtained from the suggested analytic approach with those calculated with a deterministic Boltzmann transport equation solver. Both sets of DFs are then used in our hot-carrier degradation model to calculate changes in the linear drain current as a function of stress time. Good agreement with experimental data is achieved for both versions of the model.