The addition of a noble metallization layer to doped polysilicon results in the formation of a galvanic cell when the composite is submerged in aqueous hydrofluoric acid. A corrosion current created by the galvanic cell promotes the electrochemical etching of silicon in contact with the acidic solution. Here, we demonstrate the galvanic corrosion of phosphorus-doped polysilicon when a gold metallization layer is used. As a consequence of galvanic corrosion, a number of significant changes to the polysilicon structural layers are observed including a finite polysilicon etch rate, an increase in electrical resistance (both ohmic and non-ohmic), a change in curvature (i.e. mechanical shape), and a decrease in mechanical resonant frequency. The observed change in electrical and mechanical performance on micromechanical structures necessitates more careful consideration of the post-processing procedures, as well as the choice of device metallization layer. The physical impact of corrosion becomes even more significant as device scale is decreased.
Galvanic Cell Formation During MEMS Release Processes: Implications for Sub-Micron Device Fabrication
- Views Icon Views
- Share Icon Share
- Search Site
Miller, DC, Gall, KA, & Stoldt, CR. "Galvanic Cell Formation During MEMS Release Processes: Implications for Sub-Micron Device Fabrication." Proceedings of the ASME 2004 International Mechanical Engineering Congress and Exposition. Microelectromechanical Systems. Anaheim, California, USA. November 13–19, 2004. pp. 35-44. ASME. https://doi.org/10.1115/IMECE2004-62088
Download citation file: