Sensor-Driven Reliability and Wearout Management

In this article, we propose two new approaches to improve existing DRM (dynamic reliability management) methodology First, we propose reliability sensors that use small replicated circuits to directly measure device wearout on the chip. A direct degradation measurement by these sensors removes a layer of uncertainty introduced because of inaccurate calibration of the degradation models. Note that, despite using the degradation sensors, we still require the degradation models in order to make reliability projections for the chip's remaining lifetime. Aggressive oxide thickness scaling has caused large vertical electric fields in MOSFET devices, a situation that makes oxide breakdown a crucial issue when supply voltage is not scaled as aggressively as transistor feature size. It therefore becomes increasingly difficult to ensure the reliability of ICs over their lifetime.