Wenfeng Zhang, Tomonori Nishimura, Akira Toriumi
Abstract We report on the GeO2 quality dependence of the band alignment at the GeO2/Ge interface studied by internal photoemission spectroscopy. Two kinds of Au/GeO2/Ge capacitor with similar GeO2/Ge interfaces but distinct GeO2 bulk properties were compared. The conduction band offset at the GeO2/Ge interface was revealed to be insensitive to GeO2 bulk properties, while a high density of states (DOS) near the conduction band edge of GeO2 was found to depend on GeO2 quality. Such DOS elimination led to leakage current suppression and electron mobility enhancement in Ge n-channel MOSFETs with improved GeO2 quality.