Mobility models for ZnO TFTs

ZnO device technology provides numerous possible TFT applications. This paper investigates the transport properties in thin nanocrystalline ZnO films. Since these devices are bottom-gate controlled, their characteristics reveal the properties of the back channel located at the interface. Guided by systematic experimental results, we focus on analytical models matching the mobility behavior in ZnO TFTs. The gate leakage and subthreshold leakage currents are much lower than the drain current in inversion, where the mobility model holds. We present appropriate parameter extraction methods for two particular mobility models. A good agreement is obtained between the low temperature measurements and the models proposed.