Bias Dependence of Total Ionizing Dose Effects in SiGe-SiO_2/HfO_2\ pMOS FinFETs.

The total ionizing dose (TID) response of double-gate SiGe-SiO_2/HfO_2 \ pMOS FinFET devices is investigated under different device bias conditions. Negative bias irradiation leads to the worst-case degradation due to increased hole trapping in the HfO_2 layer, in contrast to what is typically observed for devices with SiO_2 or HfO_2 gate dielectrics. This occurs in the devices because radiation-induced holes that are generated in the SiO_2 interfacial layer can transport and become trapped in the HfO_2 under negative bias, leading to a more negative threshold voltage shift than observed at 0 V bias. Similarly, radiation-induced electrons that are generated in the SiO_2 interfacial layer can transport into the HfO_2 and become trapped under positive bias, leading to a more positive threshold voltage shift than observed at 0 V bias. [ABSTRACT FROM PUBLISHER]