Direct-written polymer field-effect transistors operating at 20 MHz

TL;DR

This paper demonstrates printed polymer field-effect transistors that operate at 20 MHz using scalable, mask-less fabrication techniques, combining laser-sintered metal electrodes with high-mobility polymer semiconductors.

Contribution

It introduces a scalable, mask-less fabrication process for high-speed polymer FETs reaching 20 MHz, surpassing previous speed limitations without complex lithography.

Findings

Polymer FETs operate up to 20 MHz.

Scalable, mask-less fabrication process achieved.

Reduced parasitism to 0.19 pF mm-1.

Abstract

Printed polymer electronics has held for long the promise of revolutionizing technology by delivering distributed, flexible, lightweight and cost-effective applications for wearables, healthcare, diagnostic, automation and portable devices. While impressive progresses have been registered in terms of organic semiconductors mobility, field-effect transistors (FET), the basic building block of any circuit, are still showing limited speed of operation, thus limiting their real applicability. So far, attempts with organic FET to achieve the tens of MHz regime, a threshold for many applications comprising the driving of high resolution displays, have relied on the adoption of sophisticated lithographic techniques and/or complex architectures, undermining the whole concept. In this work we demonstrate polymer FETs which can operate up to 20 MHz and are fabricated by means only of scalable printing techniques and direct-writing methods with a completely mask-less procedure. This is achieved by combining a fs-laser process for the sintering of high resolution metal electrodes, thus easily achieving micron-scale channels with reduced parasitism down to 0.19 pF mm-1, and a large area coating technique of a high mobility polymer semiconductor, according to a simple and scalable process flow.