Effect of BTI Degradation on Transistor Variability in Advanced Semiconductor Technologies

The effect of PMOS transistor negative bias temperature instability (NBTI) on product performance is a key reliability concern. As technology scales and device dimensions shrink, the trend in the V _T variability at both time zero and after NBTI aging increases. The time0 V _T variability can be explained by the random nature of dopants, whereas the randomly generated defects in the gate oxide can account for the aging-induced device DeltaV _T variability. This paper focuses on the bias temperature instability stress-induced device DeltaV _T variability and the trend across several technology generations. The remarkable correlation of aging-induced DeltaV _T variability to the gate oxide area suggests that the continued device geometry scaling will increase the aging-induced variability. For the first time, aging-induced DeltaV _T variability was characterized on transistors fabricated with high-kappa gate dielectric that also showed similar dependence to the gate oxide area.