Metal-assisted chemical etching of silicon 3D nanostructure using direct-alternating electric field

Metal-assisted chemical etching (MaCE) of silicon (Si) is a well-used method for the fabrication of Si nanostructures. To simplify the control etching for the fabrication of Si 3D nanostructures, we developed a new method using direct-alternating electric field to control the etching direction. We examined the MaCE process in the electric field, and evaluated the effect of different electric field frequencies and ultrasonic ion bubbles on the production of Si nanostructures. The results demonstrate that electric fields can effectively control etching direction and can be used to fabricate Si 3D nanostructures. Optimization of the electric current density and electric field frequency range has been performed.