Impact of stress acceleration on mixed-signal gate oxide lifetime

A methodology to estimate the lifetime due to gate oxide breakdown (GOBD) is presented. The results of this analysis show that devices in analog circuits experience unequal stress acceleration and this impacts lifetime estimates at use conditions and can cause some devices to fail relatively more frequently under accelerated conditions in comparison with use conditions. We calculate the impact of voltage and temperature acceleration on circuits by combining the impact of voltage and temperature acceleration on each device to find the circuit-level acceleration factors. Because the acceleration factors are not constant for analog circuits, we propose to use reliability simulation to properly estimate acceleration factors under the uneven stress conditions experienced by mixed-signal circuits. The acceleration factors can then be used to estimate circuit lifetime at use conditions, given empirical data on failure rates of chips at high temperature and voltage stress conditions.