Reported Atomic Layer Etching (ALE) Chemistries for Metal Oxides and Metals

This table compiles reported atomic layer etching (ALE) chemistries for metal oxides and metals, highlighting the crucial role of oxidation in enabling self-limited etching. The Materials column lists representative oxides (HfO₂, ZnO, TiO₂, Al₂O₃) and their corresponding metals (W, Co, Pt, Cu) investigated for ALE. The Modification column specifies the reactants used for surface preparation or oxidation, such as BCl₃, acetylacetone, Sn(acac)₂, and O₂, while the Removal column indicates the agents responsible for removing the modified layer, including Ar plasma, HF–pyridine, and HCOOH. Together, these entries show that oxides exhibit more favorable reactions with halogen-based species like BCl₃ than their metallic counterparts, demonstrating that oxidation is often a prerequisite for achieving atomic-scale precision and selectivity in ALE of metals and metal oxides.

Data derived from Xia Sang and Jane P. Chang (2020). “Physical and chemical effects in directional atomic layer etching.” Journal of Physics D: Applied Physics, 53(18), 183001. DOI: https://doi.org/10.1088/1361-6463/ab6d94.