Physical Study of Low-frequency TDDB Lifetime Deterioration in Advanced FinFETs

In this work, we explored the TDDB TTF (time-to-fail) deterioration of advanced n-FinFETs under low-frequency stress by analyzing the electrical parameter degradation during the stress. The dielectric relaxation of the high-k layer and Maxwell-Wagner instability of the bi-layer gate stack were analyzed. The TDDB lifetime deterioration under low frequency is physically attributable to the charges accumulated at the high-k (HK)/interfacial layer (IL) interface due to Maxwell-Wagner instability that generates additional defects in IL during the low-frequency AC TDDB stress.