Detailed investigations of charge trapping mechanisms have revealed a very specific picture of defects in the oxide of MOSFETs. Important features of these defects, such as the existence of metastable states, were indicated by time-dependent defect spectroscopy. These insights, together with the theoretical foundation provided by the non-radiative multi-phonon (NMP) theory, led to the development of the four-state NMP model. This model describes charging processes of oxide defects microscopically, and it is able to unify reliability phenomena such as bias temperature instability, random telegraph noise and stress-induced leakage currents. Furthermore, it correctly describes the continuous degradation measured on large-area devices and the discrete trapping events observed on nanoscale devices, using the same parameters. We finally also demonstrate how this comprehensive validity can be exploited to efficiently extract the physical model parameters in order to simulate the variability and reliability of nanoscale devices.
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