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.