Energy-band alignments at ZrO[sub 2]∕Si, SiGe, and Ge interfaces

The energy-band alignments for the ZrO2∕Si, ZrO2∕Si0.75Ge0.25, and ZrO2∕Ge interfaces have been studied using x-ray photoemission. The valence-band offsets of ZrO2∕Si, ZrO2∕Si0.75Ge0.25, and ZrO2∕Ge interfaces are determined to be 2.95, 3.13, and 3.36eV, respectively, while the conduction-band offsets are found to be the same value of 1.76±0.03eV for three interfaces. The upward shift of valence-band top accounts for the difference in the energy-band alignment at three interfaces.