Model for NBTI in p-MOSFETs with ultra thin nitrided gated oxides

Negative bias temperature instability (NBTI) in p-MOSFETs is known as a major reliability issue for microelectronic devices. It has been suggested that NBTI is related to the generation of defects at the Si/SiO₂ interface during the electrical stress. In this work, the degradation of the threshold voltage, mobility and the drain current of p-MOSFET´s with ultrathin nitrided gate oxides during NBTI stress is modelled providing a physical basis as to why nitridation of oxides increases NBTI. This model includes a gaussian spread of activation energies of the Si₃≡Si· centers (so called P_b0 centres), as well as the field dependence of the mean activation energy.