Nonconducting RF and DC Hot Carrier Stresses in 14/16-nm FinFETs for RF Power Amplifiers

Hot carrier reliability under nonconducting (NC) RF and dc stresses is measured and modeled on 14/16-nm FinFETs used for RF PAs. The impact of stress on I - V and RF parameters is examined. RF parameter stress response suggests that degradations are located near the drain end of the channel within the pinch-off region. For classic V-gs = 0 V OFF-state RF stress, quasi static-approximation (QSA) significantly underestimates degradation, necessitating measurement-based lifetime modeling. At near-threshold V-gs, a condition of interest for our PAs, the degradation shows significant die-to-die variations dominated by variations of the subthreshold channel current that initiates the hot carriers. Modeling accounting for the subthreshold channel current variations shows that the near-threshold RF stress is approximately quasi-static. The results show that these FinFETs provide enough margins against NC RF stress for the intended PA applications.