A comparison of Ga:ZnO and Ga:ZnO/Ag/Ga:ZnO source/drain electrodes for In-Ga-Zn-O thin film transistors

Abstract

We compared the characteristics of single Ga:ZnO (GZO) and GZO/Ag/GZO multilayer electrodes for source/drain (S/D) contacts in amorphous In-Ga-Zn-O (a-IGZO)-based thin film transistors (TFTs). Due to the existence of a Ag metallic layer between the GZO layers, the GZO/Ag/GZO multilayer electrode exhibited low sheet resistance (3.95 ohm/sq.) and resistivity (3.32 x 10(-5) ohm-cm). The saturation mobility (10.2 cm(2) V-1 s(-1)) of the a-IGZO TFT with GZO/Ag/GZO S/D electrodes is much higher than that attained for the a-IGZO TFT with single GZO S/D electrodes (0.7 cm(2) V-1 s(-1)) due to the lower resistivity of the GZO/Ag/GZO multilayer S/D electrode. Furthermore, it is expected that the high transparency of the GZO/Ag/GZO multilayer will allow for the possible realization of fully transparent a-IGZO TFTs. (C) 2012 Elsevier Ltd. All rights reserved.