Interfacial and Electrical Properties of Ge MOS Capacitor by ZrLaON Passivation Layer and Fluorine Incorporation

Ge Metal-Oxide-Semiconductor (MOS) capacitor with HfTiON/ZrLaON stacked gate dielectric and fluorine-plasma treatment is fabricated, and its interfacial and electrical properties are compared with its counterparts without the ZrLaON passivation layer or the fluorine-plasma treatment. Experimental results show that the sample exhibits excellent performances: low interface-state density (3.7×10¹¹ cm^-2eV^-1), small flatband voltage (0.21 V), good capacitance-voltage behavior, small frequency dispersion and low gate leakage current (4.41×10^-5 A/cm² at V_g = V_fb + 1V). These should be attributed to the suppressed growth of unstable Ge oxides on the Ge surface during gate-dielectric annealing by the ZrLaON interlayer and fluorine incorporation, thus greatly reducing the defective states at/near the ZrLaON/Ge interface and improving the electrical properties of the device.