High mobility of pentacene field-effect transistors with polyimide gate dielectric layers

Polyimide gate dielectric layers cured at 180 degreesC have been employed to fabricate high-quality pentacene field-effect transistors on polyethylenenaphthalate-based films. The surface roughness (root-mean square) of gate dielectric layers characterized by atomic force microscopy is only 0.2 nm, while that of the base film is 1 nm. The transistors with pentacene channel layers deposited on 990 nm polyimide gate dielectric layers attain the on/off ratio of 10(6) and mobility of 0.3 cm(2)/V s. Furthermore, by decreasing the thickness of polyimide gate dielectric layers down to 540 nm, the mobility is enhanced up to 1 cm(2)/V s. (C) 2004 American Institute of Physics.