Advanced Metal-Assisted Chemical Etching Using HF Vapor and Ozone for MEMS Process

This study proposes a next-generation anisotropic etching method that utilizes vaporized HF and ozone in the metal-assisted chemical etching (MACE) process for the first time. The etching behavior and mechanisms under various gas-phase MACE conditions were analyzed, achieving an etching rate 70 times faster than conventional gas-phase MACE, even at room temperature. Using optimized gas-phase MACE, high-quality Si nanowire structures were fabricated, and excellent responsivity was experimentally demonstrated in a dopant-free nanowire photodetector.