Self-formed copper oxide contact interlayer for high-performance oxide thin film transistors

Oxide thin film transistor employing copper source/drain electrodes shows a small turn on voltage and reduced hysteresis. Cross-sectional high-resolution transmission electron microscopy image confirmed the formation of ∼4 nm CuOx related interlayer. The lower bond-dissociation energy of Cu-O compared to Si-O and In-O suggests that the interlayer was formed by adsorbing oxygen molecules from surrounding environment instead of getting oxygen atoms from the semiconductor film. The formation of CuOx interlayer acting as an acceptor could suppress the carrier concentration in the transistor channel, which would be utilized to control the turn on voltage shifts in oxide thin film transistors.