High-mobility Ge nMOSFETs with ZrO2 gate dielectric are demonstrated and compared against transistors with different interfacial properties of ozone (O3) treatment, O3 post-treatment and without O3 treatment. It is found that with O3 treatment, the Ge nMOSFETs with ZrO2 dielectric having a EOT of 0.83 nm obtain a peak effective electron mobility (μeff) of 682 cm2/Vs, which is higher than that of the Si universal mobility at the medium inversion charge density (Qinv). On the other hand, the O3 post-treatment with Al2O3 interfacial layer can provide dramatically enhanced-μeff, achieving about 50% μeff improvement as compared to the Si universal mobility at medium Qinv of 5 × 1012 cm−2. These results indicate the potential utilization of ZrO2 dielectric in high-performance Ge nMOSFETs.

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High mobility Ge nMOSFETs with ZrO2 gate dielectric are demonstrated and compared against transistors with Al2O3/ZrO2 , ZrO2, and O3 /ZrO 2 gate dielectrics. The Al2O3/ZrO2 provides for dramatically enhanced-effective electron mobility ( μeff ), boosting transistor drive current. Ge nMOSFETs with the Al2O3 /ZrO2 gate insulator achieve a 50% μeff improvement as compared to the Si universal mobility at an inversion charge density ( Qinv ) of 5 × 10 12 cm -2 . An Al2O3 interfacial layer leads to a boost in μeff but increases capacitance equivalent thickness (CET). Utilizing O3 oxidation of Ge surface, Al2O3 -free Ge nMOSFETs having a CET of 1.1 nm obtains a peak μ eff of 682 cm2 /Vs, which is higher than that of the Si universal mobility at the similar Qinv .