Microsoft Corporation
Transistor aging monitor circuit for increased stress-based aging compensation precision, and related methods

Abstract:

A stress-based aging monitor circuit includes a reference ring oscillator circuit and a stressed ring oscillator circuit that each include transistors like the transistors in a circuit to be monitored. Transistors in the stressed ring oscillator circuit receive a negative gate to source voltage bias while the reference ring oscillator is protected from stress. To measure performance degradation due to stress-based aging, the switching frequencies of the reference ring oscillator circuit and the stressed ring oscillator circuit are compared. The reference ring oscillator and the stressed ring oscillator include stress-enhanced inverter circuits configured to amplify stress-based aging effects to increase sensitivity to the performance degradation caused by stress-based aging. Increased sensitivity increases the precision (e.g., higher resolution) of a supply voltage guard band adjustment used to compensate for the performance degradation to reduce or avoid overcompensating for the effects of stress-based aging.