Negative bias temperature instability (NBTI) is a common phenomenon in a p-channel MOSFET device under a negative gate-to-source voltage at a high stress temperature. This paper presents the NBTI characterisation based on different analysis methods and stress conditions on p-MOSFET devices. The atomic hydrogen concentration is probed at interface, Poly-Si and channel of p-MOSFET under study using SILVACO TCAD tool. In addition, the behaviour of the permanent and recoverable component was investigated based on AC stress at different stress conditions using Modelling Interface Generation (MIG) tool. The results show that increases in temperature, negative voltage stress gate and decreases in frequency increase the threshold voltage shift, thus enhancing NBTI degradation.