ScholarWorks@성균관대학교

초록

Two-dimensional (2D) transition metal dichalcogenides (TMDs) such as 2D MoS2 exhibit diverse electronic and optoelectronic properties depending on their thickness, making reliable layer control essential for their integration into advanced materials and devices. As device architecture evolves into three-dimensional configurations, highly layer controlled isotropic etching has become increasingly important. In this study, we introduce an isotropic thermal atomic layer etching (ALE) process of 2D MoS2 monolayers for the fabrication of 3D devices through the surface modification of monolayer MoS2 by a remote oxygen plasma, followed by exposure to formic acid vapor for the removal of the oxidized monolayer by a chemical reaction under annealing conditions. This approach enables highly controllable, layer-by-layer etching while minimizing surface damage, as confirmed by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, atomic force microscopy (AFM), and device-level measurements. Additionally, transmission electron microscopy (TEM) analysis of MoS2 films suspended over three-dimensional trench structures confirmed the isotropic etching behavior. This study highlights the potential of organic-vapor-assisted ALE as a key technique for damage-free control of 2D material layer thickness, offering a promising pathway for next-generation semiconductor applications.

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