Dual threshold voltage organic thin-film transistor technology

Abstract

A fully photolithographic dual threshold voltage (VT) organic thin-film transistor (OTFT) process suitable for flexible large-area integrated circuits is presented. The nearroom-temperature (<; 95 °C) process produces integrated dual VT pentacene-based p-channel transistors. The two VT 's are enabled by using two gate metals of low (aluminum) and high (platinum) work function. The Al and Pt gate OTFTs exhibit nominally identical current-voltage transfer curves shifted by an amount ΔVT. The availability of a high-VT device enables area-efficient zero-Vos high-output-resistance current sources, enabling high-gain inverters. We present positive noise margin inverters and rail-to-rail ring oscillators powered by a 3-V supply-one of the lowest supply voltages reported for OTFT circuits. These results show that integrating nand p-channel organic devices is not mandatory to achieve functional area-efficient low-power organic integrated circuits.