Compact physical model of a-IGZO TFTs for circuit simulation

Amorphous InGaZnO (a-IGZO) is a candidate material for thin-film transistors (TFTs) owing to its large electron mobility. The development of high functionality circuits requires accurate and efficient circuit simulation that, in turn, is based on compact physical a-IGZO TFTs models. Here we propose a compact physical-based and analytical model of the drain current of a-IGZO TFTs. The model accounts for both trapped and free charges by means of an effective density of states that accurately approximate the actual a-IGZO density of states in the energy range relevant for the TFT operation. The model is implemented in a circuit simulator and it is validated with the measurements of both coplanar and staggered a-IGZO TFTs fabricated on flexible substrates.