Vapor Phase Metal-assisted Chemical Etching of Silicon
Owen J. Hildreth, Daniel R. Schmidt
This work introduces and explores Vapor Phase Metal-assisted Chemical Etching (VP-MaCE) of silicon as a method to bypass some of the challenges found in traditional Liquid Phase Metal-assisted Chemical Etching (LP-MaCE). Average etch rates for Ag, Au, and Pd/Au catalysts were established at 31, 70, and 96 nm/min respectively while the relationship between etch rate and substrate temperature was examined experimentally. Just as with LP-MaCE, 3D catalyst motion was maintained and 3D structures were fabricated using nanoparticle and lithography patterned catalysts. VP-MaCE was found to produce less microporous silicon as compared to LP-MaCE and the diffusion/reduction distance of Ag ions was significantly reduce. This process sacrifices etch rate for increased etch uniformity and lower stiction for applications in MicroElectroMechanical Systems (MEMS) processing.
Metal-assisted Chemical Etching, Vapor Phase, Nanofabrication