Ring-oscillator test-structures for sub-0.1% accuracy wafer-level characterization of active- and standby current consumption, variability, and fast aging of oscillation frequencies

this paper describes a set of ring oscillator test structures, with individually measurable static and dynamic supply currents, Nwell/Pwell leakage currents, and frequency. Purpose is to characterize frequency, leakage and aging and their variabilities, serving the stringent low-energy consumption requirements for IoT products. To obtain a comprehensive technology performance overview, these ring oscillator modules are realized in both GO1 (core oxide, four threshold flavors) and GO2 (I/O oxide, one threshold), either from inverters (mostly) or dual-input NAND/NOR cells, and with channel lengths varying from module to module.