Microstructure Formation within Films of Silicon using Electrochemical Anodization

Abstract

  The electrochemical anodization of silicon films in aqueous solutions containing hydrofluoric acid was investigated. The films were deposited onto fused quartz chips from poly-crystalline, phosphorous doped silicon using magnetron physical vapor deposition in argon plasma. X-ray diffraction from these films showed that the atomic structure of silicon was amorphous. Current-potential profiles of the films in hydrofluoric acid solutions showed a linear increase in current with increasing anodic potential, unlike the diffusion limited profiles obtained from arsenic-doped silicon (100) crystals. In order to form microstructures within selected regions of the silicon, an epoxy resin was lithographically patterned onto the surface of the silicon prior to anodization. Three-dimensional profiles of the film’s surface after removal of the resin revealed that the regions of silicon protected by the resin had formed microstructures.