Study of workload impact on BTI HCI induced aging of digital circuits

Workload characterization of digital circuits using industry standard benchmarks gives an insight into the performance and energy characteristics of processor designs. Aging studies of digital circuits due to BTI, HCI is gaining importance since a higher impact on the performance of circuits can be observed as we scale down gate dimensions. For embedded system applications, the workload may very well dictate the lifetime of a system. This article aims to study the influence of different workloads on the degradation of critical path which determines the reliability of a system. A top-down circuit activity and probability analysis is carried out leading to an accurate estimation of aging due to HCI and BTI of critical path elements at the design stage. A dedicated simulation flow has been set up, from RTL simulation down to gate level cell timing analysis mapped onto 28nm FDSOI technology from STMicroelectronics. The objective is to correlate path delay timing with aging of critical path cells. Simulation results indicate that the higher complexity of an execution program may not necessarily lead to a higher rate of degradation of the critical path considering that aging is primarily driven by the workload dependent activity and the probability of critical path combinational logic elements.