Transparent Electronics Using One Binary Oxide for All Transistor Layers

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)2Zn, in an atomic layer deposition system, the electronic properties of the binary oxide (Hf xZn1−xO2−δ 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 ≈17.9 cm2 V−1 s−1, low subthreshold swing of ≈480 mV dec−1, high Ion/Ioff ratio of >109, and excellent gate bias stability at elevated temperatures. In addition, all‐HZO inverters with high DC voltage gain (≈470), and all‐HZO ring oscillators with low stage delay (≈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.

Recent Advances in Metal-Oxide Thin-Film Transistors: Flexible/Stretchable Devices, Integrated Circuits, Biosensors, and Neuromorphic Applications

“…Therefore, there has been considerable research on transparent metal-oxide semiconductor electronic devices using low toxicity and abundant materials. Alshammari et al reported a process system in which the gate, source, drain, semiconductor, and insulating film layer constituting the transistor were all made of a hafnium zinc oxide (HZO) (Figure 4g) [74]. This study used HZO, which consists of zinc and hafnium with relatively low toxicity.…”

The Critical Role of Materials’ Interaction in Realizing Organic Field-Effect Transistors Via High-Dilution Blending with Insulating Polymers

“…Transparent and imperceptible electronics, optoelectronics, and photovoltaics have attracted increasing attention in recent years because of a wide variety of applications in flat panel displays such as see-through displays, antistatic coating, defrosters, heaters, etc . Transparent electronics have so far been dominated by wide-band-gap semiconductors, such as metal-oxides, , following the demonstration of the very first transparent ZnO-based transistor by Hoffman et al in 2003 . However, other materials such as wide-band-gap pseudohalides , and organic semiconductors , have also been shown to yield visibly transparent materials and devices.…”

Fully Transparent Transceiver Using Single Binary Oxide Thin Film Transistors

“…However, ZnO doped with Group‐IV elements such as Hf can be a better choice for alternative transparent conducting oxide. Recently, F. H. Alshammari et al reported fully transparent electronics including TFTs comprising one single binary oxide, called HZO (Hf‐doped ZnO) 16. In fact, fabricating the entire TFT device from a single indium‐free material can reduce the fabrication cost, thus avoiding the need for different deposition tools for different layers of the TFT.…”