Atomic layer deposition of high-κ dielectric for germanium MOS applications-substrate surface preparation

In this letter, we present the use of atomic layer deposition (ALD) for high-kappa gate dielectric formation in Ge MOS devices. Different Ge surface cleaning methods prior to high-kappa ALD have been evaluated together with the effects on inserting a Ge oxynitride (GeOxNy) interlayer between the high-kappa layer and the Ge substrate. By incorporating a thin GeOxNy interlayer, we have demonstrated excellent MOS capacitors with very small capacitance-voltage hysteresis and low gate leakage. Physical characterization has also been done to further investigate the quality of the oxynitride interlayer.