Si-incorporated amorphous indium oxide thin-film transistors

Amorphous oxide semiconductors, especially indium oxide-based (InO_x) thin films, have been major candidates for high mobility with easy-to-use device processability. As for a dopant in an InO_x semiconductor, we proposed Si as a strong oxygen binder to design a thin-film transistor (TFT) channel for the suppression of unstable oxygen vacancies in InO_x. In this review, we focus on the overall properties observed in Si-incorporated amorphous InO_x TFTs in terms of bond-dissociation energy, Gibbs free energy, Si-concentration dependence, carrier transport mechanism, and bias stress instability. In comparing low and high doping densities, we found that the activation energy and density of states decreased at a high Si concentration in InO_x TFTs, implying that the trap density was reduced. Furthermore, the inverse Meyer-Neldel rule observed in the highly Si-doped InO_x TFT indicated reasonable ohmic contact. With simple element components based on InO_x, it is possible to systematically discuss vacancy engineering in terms of conduction properties.