Si-incorporated amorphous indium oxide thin-film transistors

Amorphous oxide semiconductors, especially indium oxide-based (InOx) thin films, have been major candidates for high mobility with easy-to-use device processability. As for a dopant in an InOx 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 InOx. In this review, we focus on the overall properties observed in Si-incorporated amorphous InOx 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 InOx TFTs, implying that the trap density was reduced. Furthermore, the inverse Meyer-Neldel rule observed in the highly Si-doped InOx TFT indicated reasonable ohmic contact. With simple element components based on InOx, it is possible to systematically discuss vacancy engineering in terms of conduction properties. (C) 2019 The Japan Society of Applied Physics