Methods for wet atomic layer etching of molybdenum in aqueous solution

Abstract

Methods are provided for etching molybdenum in a wet ALE process. The methods disclosed herein use a wide variety of techniques and wet etch chemistries to oxidize a molybdenum surface and form a self-limiting, molybdenum oxide passivation layer in a surface modification step of the wet ALE process. In the wet ALE processes and methods disclosed herein, self-limiting behavior is provided in the oxidation step by adding a polydentate ligand to an aqueous oxidizing solution. The polydentate ligand reacts with and binds to the oxidized molybdenum surface to form a stable, ligand-molybdenum oxide complex, which is insoluble within the aqueous oxidizing solution. The insolubility of the ligand-molybdenum complex in the aqueous oxidizing solution provides self-limiting behavior in the oxidation step. After forming the molybdenum oxide passivation layer, the passivation layer is selectively removed in a dissolution step of the wet ALE process to etch the molybdenum surface.