A HCI-hardened self-healing operational amplifier circuit

In this paper, a self-healing operational amplifier circuit to deal with hot carrier injection (HCI) effect is proposed. An inverter-based operational amplifier is implemented. The influence degree of HCI effect to performance of the operational amplifier is studied which utilizes an equivalent circuit model of HCI effect. A monitoring circuit is proposed to monitor the degree of HCI degradation. A charge pump circuit is utilized to generate a corresponding voltage according to the result of monitoring circuit. The output voltage of the charge pump circuit is feedback to tune the substrate voltage of the operational amplifier (and the monitoring circuit) to mitigate degradation. The simulation results show that the self-healing operational amplifier can maintain the performance at low temperature and room temperature for 50 years (and high temperature for 30 year) under HCI effect. The gain of the inverter-based operational amplifier without self-healing is reduced from 45 dB to 9.6 dB after 50 years, and the gain of the self-healing operational amplifier will maintain at about 46 dB among 50 years. The influence of HCI effect on bandwidth and phase margin is less than that of temperature and process corner. The lifetime of self-healing operational amplifier circuit is >5 times longer than lifetime of based on inverter operational amplifier circuit without self-healing. In addition, the self-healing operational amplifier is robust to process corner.