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

Abstract

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.