Fabrication of ordered silicon wire structures via macropores without pore wall by electrochemical etching

The formation of ordered various silicon structures was investigated by varying the parameters of electrochemical etching such as current density, concentration and temperature of electrolyte, back contact material, and pre-patterned size. The silicon wires with a high aspect ratio of more than 15 are formed uniformly over a large area from a wide range of current density below J _ps and the etching rate of those are varied from 0.25 to 0.85 μm/min. We also found that there is limitation for fabricating the silicon wires as the etching depth increases. In addition, the three-dimensional multi-layer structures comprised of wires and macropores and the large and clear macropores having the diameter of more than 5 μm without additional process are produced. Furthermore, the embossed silicon wires are obtained by post-KOH etching.