Abstract The etching scale was controled by the layball process and a focus ion beam (FIB) was used to investige the dry–wet etching (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, the nano hollow formed and the Ag films sunk. However, AgGa sidewall films formed by 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.