Recent Progress on Amorphous Oxide Semiconductor Thin‐Film Transistors Using the Atomic Layer Deposition Technique

Amorphous oxide semiconductors (AOSs) have already been adopted as channel layers in display industries and have been developed for advanced electronic applications such as ultrahigh resolution, mixed reality, memory, and logic devices. Considering the limitations of reactive sputtering methods, AOSs will soon face significant challenges to improve their mobility, reliability, and device refinement as well as to control cation and anion elements. Atomic layer deposition (ALD) is a unique thin-film nanoprocess that exhibits a self-limiting surface reaction, unlike conventional physical and chemical vapor deposition. ALD enables one to easily manipulate atomic thickness and vertical composition in a film. There are several approaches to how to improve these issues of AOS materials and their associated devices by ALD. The ALD technique will open the possibility to overcome the current material and device challenges and spread out to the emerging AOS applications.