Device Characteristics and Mechanical Flexibility Simulation of Plasma-Polymer Gate Dielectrics Based Organic Thin Film Transistors

This study investigated the effects of gate dielectrics for organic thin film transistors (OTFTs). The gate dielectrics were deposited using cyclohexane with the plasma enhanced chemical vapor deposition (PECVD) method. Polyimide (PI) substrate was employed for the fabrication of pentacene OTFTs with a plasma-polymer gate insulator, Au source-drain, and Cu bottom gate electrodes. We also simulated the mechanical characteristics of an OTFT with compressive strain and tensile stress conditions for flexible devices. Pentacene field-effect transistors with cyclohexane plasma-polymer gate-dielectrics were evaluated primarily to determine their electrical properties such as mobility and threshold voltage. The transistors with cyclohexane gate-dielectrics had higher field-effect mobility, μFET = 0.84 cm²/Vs, and smaller threshold voltage, V _T = –6.8 V. Also, the mechanical flexibility simulation results showed that the deformation characteristics of OTFTs were predicted in terms of strain and internal stress.