Non-relief-pattern lithography patterning of solution processed organic semiconductors

Solution processed OTFTs (organic thin film transistors) and circuits with patterned active layers were fabricated using a non-relief-pattern, photoresist-free lithographic process. Nickel (Ni), deposited by ion-beam sputtering and patterned by lift-off, was used for the gate electrodes and silicon dioxide (SiO₂) deposited by reactive ion-beam sputtering at 80°C was used as the gate dielectric and insulation layer for wiring crossovers. Prior to the OTS layer deposition, the substrates were cleaned using oxygen plasma. After OTS patterning, to improve the metal-organic contact and device performance, a self-assembled monolayer of pentafluorbenzethiol (PFTB) were formed on the Au source/drain electrodes. The result demonstrate that surface energy patterning of solution processed organic semiconductors with performance similar to unpatterned films is possible and may provide a path to low-cost electronics.