TRANSISTOR CHARACTERISTICS WITH TA2O5 GATE DIELECTRIC

As the gate oxide thickness decreases below 2 nm, the gate leakage cur rent increases dramatically due to direct tunneling current. This larg e gate leakage current will be an obstacle to reducing gate oxide thic kness for the high speed operation of future devices. A MOS transistor with Ta2O5 gate dielectric is fabricated and characterized as a possi ble replacement for MOS transistors with ultra-thin gate silicon dioxi de. Mobility, I-d-V-d. I-d-V-g, gate leakage current, and capacitance- voltage (C-V) characteristics of Ta2O5 transistors are evaluated and c ompared with SiO2 transistors. The gate leakage current is three to fi ve orders smaller for Ta2O5 transistors than SiO2 transistors.