title: A first step in prediction of the nanoscale structure of porous silicon from processing parameters.
abstract: The present work addresses the formation of porous silicon layers by means of anodic dissolution of p- and p(+)-type boron-doped (100) silicon wafers in 15, 25, and 35 vol% HF-ethanol solutions. The study concerned the dependence of the porous silicon layer growth rate dh/dt on electric current density i as well as on HF concentration. The formation of a porous silicon layer was found to follow a generic linear relationship, in(dh/dt)--in(i), which holds irrespective of the processing conditions. The combination of two equations, experimental and theoretical, derived from Faraday's equation, allowed us to reach conclusions on the relationship between the growth rate dh/dt and the degree of porosity, constituting a first step in prediction of the nanoporous structure of silicon based on processing parameters. This electrochemical approach complements physical models of silicon pore formation.
authors.affiliation: Laboratory of Physical Metallurgy and Materials Science, Helsinki University of Technology, P.O. Box 6200, 02015 HUT, Finland.
authors.forename: E
authors.initials: E
authors.lastname: Haimi
authors.forename: V K
authors.initials: VK
authors.lastname: Lindroos
authors.forename: R
authors.initials: R
authors.lastname: Nowak
mesh_terms: D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D003461:Crystallography / Q000379:methods*; D005240:Feasibility Studies; D006858:Hydrofluoric Acid / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D016062:Porosity; D012825:Silicon / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D006858:Hydrofluoric Acid; D012825:Silicon