Improvements of Interfacial and Electrical Properties for Ge MOS Capacitor by Using TaYON Interfacial Passivation Layer and Fluorine Incorporation

Ge metal-oxide-semiconductor capacitor with HfTiON/TaYON stacked gate dielectric treated by fluorine plasma is fabricated, and its interfacial and electrical properties are compared with its counterparts without the TaYON interfacial passivation layer or the fluorine-plasma treatment. Experimental results show that the sample exhibits excellent performances: low interface-state density (2.5× 10¹¹ cm^-2 eV ^-1), small flatband voltage (0.34 V), good capacitance-voltage behavior, small frequency dispersion, and low gate leakage current (2.47 × 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 TaYON interlayer and fluorine incorporation, thus greatly reducing the defective states at/near the TaYON/Ge interface and improving the electrical properties of the device.