Systematic investigation on the effect of contact resistance on the performance of a-IGZO thin-film transistors with various geometries of electrodes

Abstract

We demonstrate the influence of the contact resistance on the electrical properties of a-IGZO thin-film transistors (TFTs) with ZrO2 gate insulator grown by rf-magnetron sputtering at room temperature by adopting various channel widths and lengths. These TFTs have all been processed at room temperature with the same channel W/L ratio (W/L = 5) but different channel widths (50, 150, 250, and 350 mu m). As the channel width increases from 50 to 350 mu m, the on-current and field effect mobility increase from 0.7 to 1 mA and 19 to 31 cm(2)/V s, respectively. However, the subthreshold swing decreases from 0.37 to 0.19 V/decade. These results show that the contact resistance strongly affects the device performances and should be considered in these applications. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim