High Performance MOCVD-Grown ZnO Thin-Film Transistor with a Thin MgZnO Layer at Channel/Gate Insulator Interface

Abstract

ZnO thin-film transistors (TFTs) with and without a thin MgZnO layer at the channel/gate insulator interface were fabricated using glass substrates. Both ZnO and MgZnO films were grown by metal organic chemical vapor deposition (MOCVD). The ZnO TFTs employing the MgZnO layer exhibit high performance with a field-effect mobility of , a subthreshold slope of , an on/off current ratio of , and a turn-on voltage of . This is the best performance reported to date for ZnO TFTs that are realized on glass substrates with MOCVD-grown channel layers. The ZnO TFTs without the MgZnO layer, on the other hand, exhibit poor performance, and the , , on/off current ratio, and turn-on voltage of these devices are , , , and , respectively. The superior performance of ZnO TFTs with the MgZnO layer is attributed to the larger grains in the ZnO film.