Abstract
During anodization for porous silicon formation, a nonelectrochemical dissolution reaction of porous silicon is found in addition to an electrochemical porous silicon formation reaction. The amount of dissolved silicon and the porous silicon density in the anodization process are formulated as functions of hydrofluoric acid concentration, anodic current density, and anodic time. The formulation agrees well with experimental values and shows that the average porous silicon density decreases with increasing anodic time due to a nonelectrochemical dissolution reaction.