Investigations of NBTI by conventional and new measurement methods for p-MOSFETs

The conventional and the fast pulsed IV measurements are carried out for the extraction of the threshold voltage shift for p-MOSFETs under stress. In addition, the on-the-fly interface trap (OFIT) measurement technique recently developed by our group is applied to the characterization of interface trap generation and recovery. The OFIT data are compared with those obtained using conventional charge pumping and direct-current current-voltage measurements. It is shown that the time delay during various measurements affects the measured characteristics of NBTI, which may mislead the understanding of NBTI mechanism. It is found that the interface trap generation plays a more important role in NBTI than that of oxide charges in the long time, especially for 10 years lifetime prediction. The results on the interface trap generation suggest a dispersive transport process, which indicates that the classical reaction-diffusion model should be reconsidered carefully.