Reliability of advanced high-k/metal-gate n-FET devices

Hot-carrier degradation and bias-temperature instability of FinFET and fully-depleted SOI devices with high-k gate dielectrics and metal gates are investigated. Thinner SOI results in increased hot-carrier degradation, which can be recovered by junction engineering. FinFETs with (1 1 0) Si active surfaces exhibit degradation of sub-threshold swing after hot carrier stress, indicating generation of interface states. The effect of duty cycle on bias-temperature instability modulates the quasi-steady-state trap occupancy over a broad distribution of electron trapping and de-trapping times. Only the deeper traps remain filled for low duty cycle, and shallower traps are emptied during AC stress.