Solution-processed ternary alloy aluminum yttrium oxide dielectric for high performance indium zinc oxide thin-film transistors

Abstract

In this study, we evaluated the structural, chemical, and electrical properties of ternary alloy aluminum yttrium oxide (Al2-xYxO3) films prepared by employing a low-cost spin-cast technique. Al2-xYxO3 films annealed at 400 degrees C were found to possess smooth and excellent insulating characteristics compared to their binary Al2O3 or Y2O3 film counterparts. This superior performance of the Al2-xYxO3 films as a gate insulator can be explained based on structure stabilization from the cation alloying mixing effect. The amorphous indium zinc oxide (a-IZO) thin-film transistor (TFT) with the ternary alloy Al0.45Y1.55O3 film exhibited a high mobility of 52.9 cm(2)/V, a low subthreshold gate swing of 0.19 V/decade, a threshold voltage of -0.51 V, a high ION/OFF ratio of 4 x 10(6), and good hysteresis-free stability, suggesting that the solution-based Al0.45Y1.55O3 dielectric film is an attractive candidate as a gate dielectric for high-performance and low-cost a-IZO TFTs.