Reliability simulation and circuit-failure analysis in analog and mixed-signal applications

In this paper, an effective and efficient methodology for reliability simulation is developed to bridge the gap between device-level reliability and that at product level. For the first time, reliability and circuit-failure behaviors under analog and mixed-signal operating conditions are simulated and analyzed with a high-speed Flash analog-to-digital converter (ADC) circuit developed in advanced CMOS technology. We demonstrate how the failure rate at circuit-level integrating multiple failure mechanisms is determined as a function of operating voltage and temperature. The results show that the dominant failure mechanism and failure rate could be changed by operating conditions. Based on the complete analysis of the ADC circuit operating under normal condition, negative bias temperature instability (NBTI) is the predominant failure mechanism in normal analog and mixed-signal applications, and failure rate increases with the elevated temperature. The impact of NBTI on circuit performance is addressed in detail. Two different types of degradation caused by NBTI are investigated: output voltage degradation and delay. The simulation results are verified by the field data. After exploring the reliability behaviors, a design for reliability methodologies is proposed and classified into two categories: device and circuit levels. This paper shreds light for the circuit life estimation and further reliable design.