Characteristics of as-grown hole trapping in silicon oxynitride p-MOSFETs subjected to negative bias temperature stress

As the most important reliability issue for the modern CMOS industry, p-MOSFET negative bias temperature instability (NBTI) is so serious now that limits the device lifetime. This paper addresses the characteristics of one of the oxide defects that responsible for NBTI, the as-grown hole trapping (AHT). It is found that AHT dominates NBTI at the beginning of stress, but its contribution decreases with stress time because of more generation of oxide positive charges as well as interface states. The formation of AHT is controlled by substrate hole injection which depends on the gate voltage other than temperature. Both the capture cross sections and distributions of AHT are investigated and compared with that of thicker oxides.