Dielectric Properties of Polymer Thin Films for the Organic Gate Dielectric Layer

Polymethylmethacrylate (PMMA)'s thermal and mechanical stability, high resistivity, and suitable dielectric constant make it an ideal candidate for the polymer thin film for the dielectric layer. PMMA thin films were fabricated on a glass substrate, using the spin coating process, at room temperature. The thermal-degradation temperature of PMMA was about 280°C, and the glass transition temperature (Tg) was about 110°C. To determine the effect of annealing, the coating films were annealed at 70–200°C for 60 m under argon atmosphere. The surfaces of the coating films were compact and uniform at all the annealing temperatures. The surface energies of the coating films were obtained by measuring the contact angles with deionized water and di-iodomethane. The coating films were found to have low surface energies. Up to below Tg, the dielectric constants of the coating films slightly increased owing to an increase of the total polarization arising from dipoles and trapped charge carriers. Above Tg, the coating ...