Transistor characteristics with Ta2O5 gate dielectric

As the gate oxide thickness decreases below 2 nm, the gate leakage current increases dramatically due to direct tunneling current. This large gate leakage current will be an obstacle to reducing gate oxide thickness for the high speed operation of future devices. A MOS transistor with Ta2O5 gate dielectric is fabricated and characterized as a possible replacement for MOS transistors with ultra-thin gate silicon dioxide. Mobility, I-d-V-d. I-d-V-g, gate leakage current, and capacitance-voltage (C-V) characteristics of Ta2O5 transistors are evaluated and compared with SiO2 transistors. The gate leakage current is three to five orders smaller for Ta2O5 transistors than SiO2 transistors.