Ultra-thin polymer gate dielectrics for top-gate polymer field-effect transistors

We have demonstrated top-gate polymer field-effect transistors (FETs) with ultra-thin (30–50 nm), room-temperature crosslinkable polymer gate dielectrics based on blending an insulating base polymer such as poly(methyl methacrylate) with an organosilane crosslinking agent, 1,6-bis(trichlorosilyl)hexane. The top-gate polymer transistors with thin gate dielectrics were operated at gate voltages less than −8 V with a relatively high dielectric breakdown strength (>3 MV/cm) and a low leakage current (10–100 nA/mm2 at 2 MV/cm). The yield of thin gate dielectrics in top-gate polymer FETs is correlated with the roughness of underlying semiconducting polymer film. High mobilities of 0.1–0.2 cm2/V s and on and off state current ratios of 104 were achieved with the high performance semiconducting polymer, poly(2,5-bis(3-alkylthiophen-2yl)thieno[3,2-b]thiophene.