Amorphous IGZO Thin‐film Transistors: Materials, Device Structures, Fabrications, and Application Explorations

Amorphous indium gallium zinc oxide (a‐IGZO) semiconductor is today one of the most competitive channel materials for constructing thin‐film transistor (TFT) devices in modern electronics. During the last two decades, a‐IGZO TFTs have been extensively studied, and their electrical, optoelectronic, and mechanical performances have been well optimized through material design, device structure construction, and fabrication process engineering. The obtained high‐performance a‐IGZO TFTs are widely applied in various fields ranging from microelectronics to macroelectronics. In this paper, recent progress in the research and development of a‐IGZO TFTs is reviewed from the aspects of materials, device structures, fabrication strategies, and application scenarios. The main properties of the a‐IGZO semiconducting materials are presented with a focus on their inherent molecular orbital structure and carrier transport mechanism. Then, the device structures of the a‐IGZO TFTs are thoroughly discussed, which include conventional and recently emerged hybrid and nano‐structures. The fabrication strategies are discussed by dividing them into two categories, vacuum‐based fabrications and solution‐processed methods. The applications of the a‐IGZO TFTs are reviewed in detail by taking typical examples from the literature. Finally, the recent progress of the a‐IGZO TFTs is summarized, and an outlook for the future development of the a‐IGZO technology is provided.