Editors’ Choice—Atomic Layer Etching of Tungsten Disulfide Using Remote Plasma-Induced Oxidation and Wet Etching

WS2 is an emerging semiconductor with potential applications in next-generation device architecture owing to its excellent electrical and physical properties. However, the presence of inevitable surface contaminants and oxide layers limits the performance of WS2-based field-effect transistors (FETs); therefore, novel methods are required to restore the pristine WS2 surface. In this study, the thickness of a WS2 layer was adjusted and its surface was restored to a pristine state by fabricating a recessed-channel structure through a combination of self-limiting remote plasma oxidation and KOH solution etching processes. The reaction between the KOH solution and WOX enabled layer-by-layer thickness control as the topmost oxide layer was selectively removed during the wet-etching process. The thickness of the WS2 layer decreased linearly with the number of recess cycles, and the vertical etc…