Abstract:

The electrochemical responses of heavily doped n-type single-crystal silicon (CSi) during the formation of porous silicon (PSi) layers in hydrofluoric acid-based electrolytes were investigated. A series of PSi layers were fabricated by constantly applying different anodic current densities, which were selected according to the linear polarization curve. The surface and cross-sectional morphologies of the PSi layers were studied by scanning electron microscopy. The electrochemical behavior of CSi and PSi electrodes was compared by linear sweep polarization and chronopotentiometry techniques. The important parameters associated with the electrochemical reactions at the electrodes were evaluated by analyzing the Tafel plots and chronopotentiograms obtained before and after the PSi formation. Structural models of the CSi electrode/electrolyte and PSi electrode/ electrolyte interfaces were suggested based on the experimental data. Accordingly, the interfacial characteristics of CSi and PSi electrodes were discussed.

Key words: Porous silicon, Silicon electrode interface, Corrosion rate, Open circuit potential, Polarization curve, Interface electrochemistry