High-Speed Ternary CMOS Inverter by Monolithic Integration of NbO2 Threshold Switch with MOSFET

Abstract

To realize a step-shaped ternary transistor capable of high-speed operation, NbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> threshold switch (TS) device was integrated on the drain side of the conventional MOSFET. The fast switching speed(<63ps), excellent reliability, and moderate OFF -current level of NbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> TS device enable sub-10ns clock operations of ternary CMOS inverter. For comparison, various types of TS devices were evaluated for ternary device applications. Ag-based ternary device is suitable for low-power applications due to the low operating voltage and low OFF-current of Ag-based TS device. Finally, noise margin controlled by threshold voltages of the transistor and the NbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> device was investigated for low VDD operations. Combining scaled-down TS devices with state-of-the-art transistor technology is expected to have ternary device with low VDD operation(≤0.7V).