Acceptor-like trap effect on negative-bias temperature instability (NBTI) of SiGe pMOSFETs on SRB

Abstract

In this work, the oxide electric field (Eox) reduction caused by negatively charged traps is proposed to explain the robustness of SiGe pMOSFETs to negative gate bias temperature instability (NBTI) stress. The high density of negatively charged acceptor-like traps close to the SiGe valance band (Ev) lowers the Eox and reduces the NBTI degradation at fixed overdrive. We demonstrate that trap engineering can be exploited to meet aggressive reliability requirements. Furthermore, it is predicted that there are no reliability issues in the SiGe pMOSFETs comparing with the Si counterparts.