Transistor characteristics with Ta/sub 2/O/sub 5/ gate dielectric

Abstract

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 Ta/sub 2/O/sub 5/ gate dielectric is fabricated and characterized as a possible replacement for MOS transistors with ultra-thin gate silicon dioxide. Mobility, I/sub d/-V/sub d/, I/sub d/-V/sub g/, gate leakage current, and capacitance-voltage (C-V) characteristics of Ta/sub 2/O/sub 5/ transistors are evaluated and compared with SiO/sub 2/ transistors. The gate leakage current is three to five orders smaller for Ta/sub 2/O/sub 5/ transistors than SiO/sub 2/ transistors.