Composition-Dependent Atomic Layer Etching of Multicomponent Oxide Semiconductors with Preserved Electrical Performance

Abstract

Oxide semiconductors are promising channel materials for next-generation memory device scaling, owing to their low off-state current, low-temperature processability, and excellent compatibility with back-end-of-line manufacturing. Here, we report the composition-dependent atomic layer etching (ALE) behavior of the multicomponent oxide semiconductor InGaZnOx (IGZO), enabled by a hydrogen-based surface modification chemistry. The constituent cations of IGZO exhibit markedly different reactivities toward hydrogen, allowing the overall etch rate to be systematically tuned through elemental composition. Because this reaction is largely confined to the near-surface region, ALE minimizes damage to the underlying front-channel region, achieving atomic-scale material removal with minimal degradation of electrical performance, in contrast to conventional dry-etching approaches that often degrade transistor characteristics. Leveraging this low-damage, self-limiting characteristic, we further demonstrate that ALE enables post-deposition trimming of nonuniform IGZO films conformally deposited within three-dimensional trench structures, improving step coverage to nearly 100%. These results establish hydrogen-based ALE as a versatile, composition-aware process for the atomic-scale control of multicomponent oxide semiconductor channels, offering a low-damage route toward scalable three-dimensional memory device architectures.