Impact of NBTI on performance of domino logic circuits in nano-scale CMOS

Abstract

Negative Bias Temperature Instability (NBTI) in pMOS transistors has become a major reliability concern in the state-of-the art digital circuit design. This paper discusses the effects of NBTI on 32nm technology high fan-in dynamic OR gate, which is widely used in high-performance circuits. The delay degradation and power dissipation of domino logic, as well as the Unity Noise Gain (UNG), are analyzed in the presence of NBTI degradation. We have shown the degradation in the output inverter pMOS transistor of the domino gate has a dominant impact on the delay in comparison with the keeper impact. Based on this analysis we have proposed that upsizing just the output inverter pMOS transistor can compensate for the NBTI degradation. Moreover, the impact of tuning the duty cycle of the clock has been investigated. It has been shown that although the keeper and the precharge transistors experience more NBTI degradation by increasing the low level in the clock signal, the total performance of the circuit will improve. We have also proposed an adaptive compensation technique based on Forward Body Biasing (FBB), to recover the performance of the aged circuit.