Preparation of Silicon Nanopillar Arrays Using Reactive Ion Etching with a Faraday Cage

Faraday cages are extensively utilized in plasma-based etching and deposition processes to regulate ion behavior due to their shielding effect on electromagnetic fields. Herein, vertical silicon nanopillar arrays are fabricated through SF₆ and O₂ reactive ion etching. By incorporation of a Faraday cage in the plasma equipment, the impact of the Faraday cage on the morphology of the silicon nanopillars is analyzed; the Faraday cage blocks out the sputtered particles and eradicates the formation of silicon nanograss. Specifically, it regulates the value and dispersion of the etching rate by varying the mesh number and the distance from the grid wires to the sample surface. A “flattening belly” phenomenon of silicon nanopillars associated with the temperature is resolved using segmented multiple etching processes. This research contributes to an in-depth analysis of plasma etching using a Faraday cage as well as potential applications for silicon nanopillars.