Accurate and Compact Small-Signal Modeling of Zinc-Oxide Thin-Film Transistors for Operation in the GHz Regime

Large-area electronic (LAE) thin-film transistors (TFTs) with GHz operation frequencies have enabled LAE-based wireless systems [1] . This motivates accurate modeling of GHz TFTs, but existing approaches are limited for two reasons [2] , [3] : (1) analytical models with numerous parameters are impractical for simulating complex circuits and systems; (2) important losses in the GHz regime are overlooked. Therefore, a non-quasi-static small-signal model has been proposed for GHz zinc-oxide (ZnO) TFTs [1] . However, to match measurements, this model requires an unrealistic value for gate resistance R G , which is a key frequency-limiting factor. Here we present an accurate and compact small-signal TFT model that includes losses from channel resistance, which are shown to be critical to GHz TFT performance. With physically realistic parameter values, this approach can precisely model GHz ZnO TFTs in both linear and saturation regimes. The model illuminates that reducing channel resistance losses is the key to raising the TFT’s operation frequency.