SILC during NBTI Stress in PMOSFETs with Ultra-Thin SiON Gate Dielectrics

Negative bias temperature instability (NBTI) and stress-induced leakage current (SILC) both are more serious due to the aggressive scaling lowering of devices. We investigate the SILC during NBTI stress in PMOSFETs with ultra-thin gate dielectrics. The SILC sensed range from -1V to 1V is divided into four parts: the on-state SILC, the near-zero SILC, the off-state SILC sensed at lower positive voltages and the one sensed at higher positive voltages. We develop a model of tunnelling assisted by interface states and oxide bulk traps to explain the four different parts of SILC during NBTI stress.