First-Principles Study of GeO2/Ge Interfacial Traps and Oxide Defects

An important issue concerning Ge-MOSFETs is the quality of gate dielectric/Ge interfaces. The reported values for energy positions of the interfacial defects in Ge-MOSFETs vary across the literature. High interfacial trap density (D_it) close to the conduction band minimum (CBM) and/or the valence band maximum (VBM) have been reported [1, 2]. In this work, using density functional theory, we propose possible origins of the various GeO₂/Ge interfacial states, and also address native defects in GeO₂ to show their possible influence on Ge-MOSFETs.