Layer By Layer Etching Of CVD MoS₂ With Low Damage Using Atomic Layer Etch System

Analysis dynamic product of semiconductor industry at domestic and international, size is to the development of more smaller downward trend, function is to the development of stronger trend. Industrial application of every kind of high characteristic semiconductor materials can produce amount wealth.The properties of two-dimensional MoS2 materials are strongly dependent on their number of layers and a concise, effective, and low damage method to control the number of MoS2 layers is strongly desirable for the fabrication of two-dimensional MoS2 devices. CVD, PECVD and anther synthetic method can obtain high-quality samples, but it is difficultly control the termination of point synthesis.Here, we propose layer-by-layer etching of MoS2 to monolayer by the atomic layer etching (ALET) method composed of cyclic processing of Cl radical adsorption and Ar+ ion beam desorption. No MoS2 etching was observed with a Cl radical adsorption step only or with a low energy (<20eV) Ar+ ion beam desorption step only, however, by the sequential etching composed of the Cl radical adsorption step and the following Ar+ion beam desorption step, complete etching of one monolayer MoS2 could be achieved. Raman microscopy, x-ray photoelectron spectroscopy (XPS), and atomic force microscopy proved that one monolayer MoS2 is perfectly removed by each cycle of ALET. Therefore, by the cyclic ALET processing of a multilayer MoS2 composed of the Cl radical adsorption step and the Ar+ ion beam desorption step, the number of MoS2 layer could be precisely controlled. In addition, after the MoS2 ALET, from Raman spectroscopy and XPS, no noticeable damage and etch residue to the exposed MoS2 layer surface was observed.