Effect of Microwave Annealing on Transparent In–Ga–ZnO Thin-Film Transistors With Graphene Source and Drain Electrodes

Abstract

In this letter, we investigated the effects of microwave heat treatment on amorphous In–Ga–ZnO (a-IGZO) thin-film transistors (TFTs) with transparent graphene source and drain (S/D) electrodes. Microwave annealing (MWA) was simultaneously applied to post-deposition annealing of the a-IGZO channel layer and post-metallization annealing of the graphene S/D electrode, and then, the influence of MWA on the a-IGZO channel and graphene S/D electrode was evaluated and compared with conventional thermal annealing. We measured the ${I}$ – ${V}$ characteristics of the a-IGZO TFTs, analyzed the trap density of the channel layer, the interface trap density between the gate oxide and the channel, and the instability of device was evaluated. In addition, the effect of MWA on the contact resistance and process stability of transparent graphene electrodes was analyzed. As a result, we improved the electrical properties of the a-IGZO TFTs, simplified the annealing step, and reduced the thermal budget without damaging the graphene S/D electrode for transparent and flexible displays.