Contact Length Scaling in Staggered Organic Thin-Film Transistors

Abstract

In this letter, the contact length (source and drain electrodes length) scaling potential in staggered organic thin-film transistors (OTFTs) was studied. We performed the effect of gate–source voltage, channel length, semiconductor film thickness, mobility, material disorder, anisotropy of mobility, and Schottky barrier between organic semiconductor and source/drain electrodes on the contact length downscaling, and found that the contact resistance do not increase until the contact length is scaled down to sub-500 nm. Importantly, the cutoff frequency ( $f_{T}$ ) of OTFTs was described and it was found that $f_{T}$ would increase with the decrease of contact length and the highest $f_{T}$ could be obtained with contact length in the range of sub-100 nm with Ohmic contacts. This letter showed excellent contact length scaling potential of OTFTs and provided guidelines for the design of high frequency, low-cost, and printable OTFTs.