Vapor-Phase Synthesis of High-<EM>k</EM>, Ultrathin Polymer Dielectric with Molecular Thin, Hydrophobic Skin Layer for Extremely Stable Organic Thin-Film Transistor (OTFT) Operation
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초록
내용
A sub-20 nm, high-k copolymer dielectric with hydroxyl functionality was synthesized via initiated chemical vapor deposition (iCVD). The inherently dry environment offered by the vapor-phase polymer synthesis prompted the snuggling of polar hydroxyl functionalities into the bulk polymer film to form a molecular thin hydrophobic skin layer at its surface. The chemical composition of the copolymer dielectric was optimized systematically to achieve high dielectric constant (k~6.2) as well as extremely low leakage current densities even with sub-20 nm thickness, leading to one of the highest capacitance achieved by a single polymer dielectric to date. Exploiting the structural advantage of the crosslinked high-k polymer dielectric, high-performance OTFTs with the suppressed hysteresis were obtained owing to the hydrophobic skin layer. Furthermore, the OTFTs with the copolymer dielectric showed an unprecedentedly excellent operational stability.