Threshold Voltage Control of Pentacene Thin-Film Transistor with Dual-Gate Structure

This paper presents a comprehensive study on threshold voltage (V-th) control of organic thin-film transistors (OTFTs) with dual-gate structure. The fabrication of dual-gate pentacene OTFTs using plasma-enhanced atomic layer deposited (PEALD) 150 nm thick Al2O3 as a bottom gate dielectric and 300 nm thick parylene or PEALD 200 nm thick Al2O3 as both a top gate dielectric and a passivation layer was investigated. The V-th of OTFT with 300 nm thick parylene as a top gate dielectric was changed from 4.7 V to 1.3 V and that with PEALD 200 nm thick Al2O3 as a top gate dielectric was changed from 1.95 V to -9.8 V when the voltage bias of top gate electrode was changed from -10 V to 10 V. The change of Vth of OTFT with dual-gate structure was successfully investigated by an analysis of electrostatic potential.