Two-step etching mechanism of Ag-Si nanostructure with various Ag nanoshape depositions

Nanopattems can be structured using either dry-etching or wet-etching. In this study, Ag/Si thin film was used to prepare the nano-hollow structures using the two step selective etching method (dry-wet etching, DWE). The etching scale was controlled by the layball process and a Focus Ion Beam (FIB) was used to investigate the DWE mechanism. Increasing the beam current of dry-etching raised the height of nano prominent structures, but deteriorated the interface of Ag/Si film, and even damaged the Ag film because of Ga⁺ bombardment. Regardless of the Ag nanoshape deposition, the residual Ag films were doped with Ga⁺ and were sensitive to DWE. After wet-etching, a nano hollow formed and the Ag films sunk. However, Ago, (Ag film doped Ga ions) sidewall films formed due to the concentration gradient and the oxidative potential and this increased the volume of microporous phases, resulting in a reduction in the depth. Also, 15-30 nm Ag nano-particles were able to enhance the DWE mechanism in the Ag/Si nanostructures.