title: Self-assembled biofilm of hydrophobins protects the silicon surface in the KOH wet etch process.
abstract: The anisotropic wet micromachining of silicon, based on a water solution of potassium hydroxide (KOH), is a standard fabrication process that is extensively exploited in the realization of very complex microsystems, which comprise cantilevers, membranes, and bridges. A nanostructured self-assembled biofilm of amphiphilic proteins, the hydrophobins, was deposited on crystalline silicon by solution deposition and characterized by variable-angle spectroscopic ellipsometry (VASE). This procedure formed chemically and mechanically stable mono- and multilayers of self-assembled proteins. The biomolecular membrane has been tested as masking material in the KOH wet etch of the crystalline silicon. The process has been monitored by VASE and atomic force microscopy measurements. Because of the high persistence of the protein biofilm, the hydrophobin-coated silicon surface is perfectly protected during the standard KOH micromachining process.
authors.affiliation: Unit of Naples-Institute for Microelectronics and Microsystems, Via P. Castellino 111, 80131 Naples, Italy. luca.destefano@na.imm.cnr.it
authors.forename: Luca
authors.initials: L
authors.lastname: De Stefano
authors.forename: Ilaria
authors.initials: I
authors.lastname: Rea
authors.forename: Annunziata
authors.initials: A
authors.lastname: Armenante
authors.forename: Paola
authors.initials: P
authors.lastname: Giardina
authors.forename: Michele
authors.initials: M
authors.lastname: Giocondo
authors.forename: Ivo
authors.initials: I
authors.lastname: Rendina
mesh_terms: D016880:Anisotropy; D018441:Biofilms; D005656:Fungal Proteins / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry*; D008567:Membranes, Artificial; D017680:Potassium Compounds / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*
chemical_list: D005656:Fungal Proteins; D006878:Hydroxides; D008567:Membranes, Artificial; D017680:Potassium Compounds; C029943:potassium hydroxide; D012825:Silicon