Metallization selection and the performance of amorphous In-Zn-O thin film transistors

Abstract

We report on the effect of two different source/drain metallizations (Ti, Mo) on the performance and stability of amorphous In-Zn-O (IZO) thin film transistors (TFTs). In the as-deposited state, stable Mo/IZO TFTs show low threshold voltage (VT) and clear drain current saturation behavior compared to Ti/IZO devices, despite both having similar channel conductivity. Low temperature annealing (200 °C) results in VT shifts in Ti/IZO TFTs (ΔVT ∼ −33 V) that are significantly larger than in Mo/IZO TFTs (ΔVT ∼ −14 V). These differences are attributed to the injection of additional carriers into the channel of Ti/IZO devices due to reaction at the unstable Ti/IZO interface.