Solution-processed amorphous ZrO2 gate dielectric films synthesized by a non-hydrolytic sol-gel route

Abstract

Solution-processed zirconium oxide (ZrO2) dielectrics were formed via a non-hydrolytic sol-gel route at low-temperature, and are suitable for flexible thin film transistor (TFT) devices. Precursor solutions with equimolar zirconium halide and zirconium alkoxide were prepared, and amorphous ZrO2 films were obtained by spin-coating and annealing at 300 °C through the direct condensation reaction between them. The ZrO2 films exhibited a high dielectric constant near 10, and a low leakage current density of 5 × 10-8 A cm-2 at a field of 1 MV cm-1. High mobility p-type pentacene TFTs were fabricated using the ZrO2 dielectrics, with a saturation field-effect mobility of 3.7 cm2 V-1 s-1, a threshold voltage of -2.7 V, an on/off ratio of 1.1 × 106 and a subthreshold swing of 0.65 V dec-1.