Abstract
A novel process is developed in which thin film transistors (TFTs) comprising one binary oxide for all transistor layers (gate, source/drain, semiconductor channel, and dielectric) are fabricated in a single deposition system at low temperature. By simply changing the flow ratio of two chemical precursors, C8H24HfN4 and (C2H5)(2)Zn, in an atomic layer deposition system, the electronic properties of the binary oxide (HfxZn1-xO2-delta or HZO) are tuned from conducting, to semiconducting, to insulating. Furthermore, by carefully optimizing the properties of the various transistor HZO layers, all-HZO thin film transistors are achieved with excellent performance on both glass and plastic substrates. Specifically, the optimized all-HZO TFTs show a saturation mobility of approximate to 17.9 cm(2) V-1 s(-1), low subthreshold swing of approximate to 480 mV dec(-1), high I-on/I-off ratio of >10(9), and excellent gate bias stability at elevated temperatures. In addition, all-HZO inverters with high DC voltage gain (approximate to 470), and all-HZO ring oscillators with low stage delay (approximate to 408 ns) and high oscillation frequency of 245 kHz are demonstrated. This approach presents a novel, simple, high performance, and cost-effective process for the fabrication of indium-free transparent electronics.