The same batch enabled threshold voltage tuning for vertically- or laterally-gated transparent InZnO thin-film transistors.

Fully transparent InZnO thin-film transistors (TFTs), with either a bottom gate or an in-plane gate device structure, were fabricated using the solution-processed SA proton conducting films as gate dielectrics. The self-assembled InZnO channel with different thickness by the gradient shadow mask was fabricated during the same batch radio-frequency magnetron sputtering. The threshold voltage can be modulated from −0.25 to +0.12 V and from −0.07 to +0.25 V by the channel layer thickness variations for the vertically-coupled and laterally-coupled InZnO TFTs, respectively. Accordingly, these InZnO TFTs can operate in either depletion or enhancement mode on the same chip. A general expression of the turn-on voltage in relation to the channel thickness is derived. The device performance with an on/off current ratio of ≥1.5 × 106, a subthreshold swing of down to 70 mV/decade, and a field-effect mobility of up to 34.3 cm2/V · s is exhibited. Our results demonstrate that the same batch channel processing is potentially applied in logic circuits or functional electronics. [ABSTRACT FROM AUTHOR]