Ring Oscillator Aging Characterization in Conventional CMOS Technologies

Ring Oscillators (RO) are widely used to capture the aging in digital circuits of advanced CMOS technology nodes. RO’s also provide critical insights into the aging of conventional CMOS technologies utilizing poly-Si gates and SiO
2
or SiON gate dielectrics. The use of an optimized Design-For-Reliability (DFR) RO allows separate measurements decoupling nMOS and pMOS aging of static and dynamic stress. It is shown that Negative Bias Temperature Instability (NBTI) dominates for short stress duration and stress voltages close to operation condition while Channel Hot Carrier (CHC) degradation is the major contributor at high stress voltage.