Random macropore formation in variously doped p-type silicon substrates (0.01-20 Ω cm) by electrochemical anodization in aqueous HF-containing dimethylsulfoxide, dimethylformamide, or acetonitrile was investigated under different operating conditions. A systematic study of the effect of the main parameters controlling the macropore formation is reported. The results revealed that the nature of organic solvent, the concentration of HF, and the substrate doping level play major roles in determining pore formation and morphology. Also, the behavior of these macropores in contact with an aqueous solution of Ag 2 SO 4 in the dark and at room temperature is investigated and a possible reaction mechanism for the deposition process is proposed.