Reaction-Diffusion (R-D) framework for interface trap generation along with hole trapping in pre-existing and generated bulk oxide traps are used to model Negative Bias Temperature Instability (NBTI) in differently processed SiON p-MOSFETs. Time, temperature and bias dependent degradation and recovery transients are predicted. Long-time power law exponent of DC degradation and uniquely renormalized duty cycle and frequency dependent AC degradation data from a wide range of sources are shown to have universal features and a broad consensus across industry/academia. These universal features can also be predicted using the classical R-D framework.