LISOCHIN: An NBTI Degradation Monitoring Sensor for Reliable CMOS Circuits

Reliability and variability issues are the biggest design challenges facing nanoscale high-speed applications. Negative bias temperature instability (NBTI) is the major reliability issues with the scaled devices. Effect of NBTI increases with the time and it increases the threshold voltage of PMOS. This paper presents an NBTI degradation sensor which monitors the change in standby leakage current (\(I_{ddq}\)) of the test circuit under the stress conditions. The performance of proposed sensor is linear and highly sensitive. Due to high sensitivity, the proposed sensor is best suited for compensation of temporal degradation during measurement. The sensitivity of the proposed sensor further increase at elevated temperature (125 \(^{\circ }\)C) compares to room temperature (27 \(^{\circ }\)C). The proposed sensor has the improvement in sensitivity of 20.12% and 74.82% as compared to CM based sensor at room temperature and elevated temperature respectively. The transimpedance of the proposed sensor is linear and the linearity is unaffected by the voltage and temperature variations. The proposed sensor is 25% smaller and has faster response compared to CM based sensor. The proposed sensor is also unaffected by the supply voltage variations.