Thin-film transistor behaviour and the associated physical origin of water-annealed In-Ga-Zn oxide semiconductor

Abstract

A transparent In-Ga-Zn oxide semiconductor was thermally annealed in an ambient atmosphere of water vapour and the associated electrical and physical properties of the film were investigated. After annealing in water vapour, the resulting thin-film transistor (TFT) exhibits n-type behaviour with a field effect mobility of 11.4 cm(2) V-1 s(-1), and an on/off current ratio of 6.65 x 10(9). The annealing process in water vapour induces changes in the elemental composition and chemical bonding states of Zn and O. These phenomena affect the changes of band alignment including the band gap and conduction band offset (Delta (E-CB - E-F)) of InGaZnO semiconductors, which is the basis for the improved operation and performance of these TFTs.