We synthesized a novel thermally-crosslinkable ormosil-based hybrid material as a solution-processable dielectric layer for organic thin-film transistors (OTFTs). Dielectrics with a thickness of 50-260 nm were fabricated via spin-coating in order to evaluate their applicability as an ultrathin gate dielectric. It was observed that the capacitance of the hybrid dielectric increases with decreasing film thickness. Hybrid dielectrics with a thickness of 260 nm and 160 nm, respectively, exhibited adequate leakage current behavior. Coplanar-type OTFTs were fabricated using each of the hybrid dielectrics (i.e., thickness of 260 nin and 160 nm). The off-current, threshold voltage, and field-effect mobility of both transistors were analyzed to investigate the effects of capacitance and film thickness on the electrical performance of the transistors. (c) 2006 Elsevier B.V All rights reserved.