Operation model with carrier-density dependent mobility for amorphous In–Ga–Zn–O thin-film transistors

Abstract An operation model for an amorphous In–Ga–Zn–O ( a -IGZO) based thin film transistor (TFT) is studied. The model is not based on the exponential tail states employed in hydrogenated amorphous Si ( a -Si:H) TFT, but on a power function of the carrier density which is observed in the TFT and Hall mobilities of a -IGZO. A 2D numerical simulator employing this model reproduced current–voltage characteristics under on operation of coplanar homojunction a -IGZO TFTs. Although the mathematical expression of the mobility is similar to the field effect mobility of a -Si:H TFT, the present model explains the temperature dependence of the on characteristics of a -IGZO TFT.