Enhanced Wear-Out Sensor Design in a 12nm Process for Separable Stress Regime Monitoring

Ring oscillators are widely used for monitoring wear-out in semiconductor devices, providing a holistic view of degradation resulting from multiple mechanisms simultaneously affecting the inverter stages. In this work we present a ring oscillator sensor architecture for isolated monitoring of the contributions of bias temperature instability (BTI) and hot carrier injection (HCI) stress regimes in both NMOS and PMOS transistors. The design contributes a topology for HCI stress isolation, explicit consideration for degradation of auxiliary transistors, and enhanced comparative analysis capability through an interwoven oscillator layout technique. The sensor variants are implemented in a 12nm FinFET process then stressed and measured using a custom automated wear-out test system built using Rust. Our measurement results agree with simulations and illustrate the differences in degradation between stress regimes in non-planar transistors.