Organic thin film transistors with HfO 2 high- k gate dielectric grown by anodic oxidation or deposited by sol–gel

Abstract

We report here on pentacene based organic field effect transistors (OFETs) with a high- k HfO 2 gate oxide. HfO 2 layers were prepared by two different methods: anodic oxidation and sol–gel. A comparison of the two processes on the electrical properties of OFETs is given. Ultra thin nanoporous (20 nm) sol–gel deposited oxide films were obtained following an annealing at 450 °C. They lead to high mobility and stable devices ( μ = 0.12 cm 2/V s). On the other hand, devices with anodic HfO 2 revealed a little bit more leaky and show some hysteresis. Anodization, however, presents the advantage of being a fully room temperature process, compatible with plastic substrates. Stability and response to a bias stress are also reported.