In this paper, we present a combined measurement/simulation method, implemented in order to estimate the spatial and energy oxide trap distribution induced by negative bias temperature instability (NBTI) stress in p-channel power U-MOSFETs. The methodology consists in analyzing the recovery phase at different bias conditions and correlating the results with TCAD numerical simulations. We found an oxide trap distribution positioned between 2.24 and 3.04 nm distant from oxide/channel interface with an energy level confined in the silicon bandgap