Germanium (Ge) has been attracting considerable attention as a high mobility channel material to enhance the performance of CMOS circuits. One of the most important issues for realization of practical Ge-MOSFET devices with superior performances is requirement to improve qualities of gate dielectric/Ge interfaces. In this work, Al2O3/Ge structures are fabricated by direct atomic layer deposition (ALD) on epitaxialy grown Ge. We indicate that ALD incubation time is fully suppressed by the ALD on a completely clean Ge surface created by Ge epitaxy on a Ge substrate. Moreover, x-ray photoelectron spectroscopy analyses reveal that unintentional formation of a GeO2 at the Al2O3/Ge interface can be almost avoided by the ALD on the epitaxial Ge whereas the interfacial GeO2 layer is present for samples exposed to the air before ALD. These results clearly indicate that direct ALD on epitaxial Ge is a very promising method to significantly improve Ge MOSFET performances.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry