Interface traps and oxide charges during NBTI stress in p-MOSFETs

This work gives an insight of the degradation mechanisms during a negative bias instability stress on ultrathin oxides (t/sub ox/ =20/spl Aring/). First, it is checked out that there is a correlation between the threshold voltage shift and the increase of interface traps density. Though, the trapping of holes into the oxide is a non-negligible component of the degradation. Applying a positive bias on the gate allows the holes to get trapped out, reducing the threshold voltage shift.