To realize high-mobility surface channel pMOSFETs on Ge, a 1.6-nm-thick SiOx passivation layer between the bulk Ge substrate and HfSiO gate dielectric was introduced. This approach provides a simple alternative to epitaxial Si deposition followed by selective oxidation and leads to one of the highest peak hole mobilities reported for unstrained surface channel pMOSFETs on Ge: 332cm2 · V-1 · s-1 at 0.05 MV/cm - a 2× enhancement over the universal Si/SiO2 mobility. The devices show well-behaved output and transfer characteristics, an equivalent oxide thickness of 1.85 nm and an ION/IOFF ratio of 3 × 103 without detectable fast transient charging. The high hole mobility of these devices is attributed to adequate passivation of the Ge surface.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering