Asymmetric energy distribution of interface traps in germanium MOSFETs with HfO2 gate dielectric

Abstract

In this work, a simple model, with a higher interface trap density in the upper half of Ge bandgap than that in the lower half, is proposed to explain the abnormal behaviors in Capacitance-Voltage characteristics of both p- and n-MOS capacitors on Ge substrate using different surface passivation. Variable rise/fall-time charging pumping measurement is used to study the energy distribution of interface trap density in HfO2 gated Ge MOSFETs. Our results reveal that Dit is higher in the upper half of the Ge bandgap than that in the lower half of the bandgap. These results are also consistent with the observation that n-channel mobility is more severely degraded compared to p-channel for Ge MOSFET. ©The Electrochemical Society.