Zirconium dioxide as a gate dielectric in metal-insulator-silicon structures and current transport mechanisms

This paper investigates the interfacial and bulk properties of zirconium dioxide as a high-k gate dielectric film and studies its current transport mechanisms. Aluminum gate/zirconium dioxide/n-type silicon (Al/ZrO/sub 2//n-Si) metal-insulator-silicon (MIS) devices with equivalent-oxide-thickness (EOT) of /spl sim/2.5 nm (with leakage current density of less than 2/spl times/10/sup -5/ A/cm/sup 2/ at 1 V accumulation bias) were fabricated and characterized using electrical and structural analysis techniques. The simulated capacitance-voltage (C-V) curve, obtained by the self-consistent solution of Schrodinger and Poisson equations, was found to fit the measured C-V curve for the minimum (inversion) and maximum (accumulation) capacitances if dielectric constant values of 15 and 25 were used for the interfacial and bulk ZrO/sub 2/ layers. It was found that the Schottky emission mechanism fits a very narrow gate voltage (V/sub g/) range of 0