A Comparison Study on the Al-based Interfacial Layers for Ge MIS Devices

Abstract

The performance of MIS devices on Ge substrate using AlN and Al2O3 as interfacial layer is investigated. Using AlN as interfacial layer can achieve lower leakage current and smaller hysteresis than using Al2O3 because AlN is a more effective barrier to against GeO volatilization and Ge diffusion. However, the interface state density of the AlN/Ge structure is poor. It is found that capping AlN on Al2O3 improves the hysteresis and leakage current while relax the interface state density degradation. It is suggested that appropriate AlN/Al2O3 stack can be used to fabricate high -quality MIS capacitor with ultra-thin effective oxide thickness.