Electrochemically driven intrusion of silver particles into silicon under polarization

The pore formation with the diameter of around 100 nm into a lightly doped p-type Si was achieved with the intrusion of silver particles by electrolysis in HF aqueous solution. The route resembles the metal-catalyzed electroless pore formation, but the present method uses anodic polarization instead of chemical etching in the presence of oxidizing agent. A microporous layer was observed around the pores formed as the tracks of silver particles. Thickness of the microporous layer around the track increased with the increase in current density. The thickness was varied in accordance with the time-programmed variation of current density. Conversely, the intrusion of silver particles seldom occurred in heavily doped p-type silicon, while micropores were formed independently of the location of the particles. The concentration of dopant affects the silver-particle-assisted porosification.