Physical modeling of hot-carrier degradation for short- and long-channel MOSFETs

We present the first physics-based model for hot-carrier degradation which is able to capture degradation in both short- and long-channel SiON nMOSFETs. Degradation is considered to be due to the breaking of Si-H bonds at the SiON/Si interface. Contrary to previous modeling attempts, our approach now correctly considers the intricate superposition of multivibrational bond excitation and bond rupture induced by a solitary hot carrier based on experimentally confirmed distributed activation energies. All processes are treated as competing pathways, leading to bond dissociation from all vibrational levels. These rates are determined by the carrier acceleration integral and by the bond energetics. The acceleration integral is calculated using the carrier energy distribution. Corresponding distribution functions are found by a thorough solution of the Boltzmann transport equation. We demonstrate that electron-electron scattering plays the dominant role. As for the bond energetics, we consider the dispersion of the activation energy as well as its reduction induced by the interaction of the bond dipole moment with the electric field. All the model ingredients are incorporated into the same simulation framework based on the deterministic solver of the Boltzmann transport equation, ViennaSHE.