The Au-assisted electroless etching of p-type silicon substrate in HF/H2O2 solution at 50 degrees C was investigated. The dependence of the crystallographic orientation, the concentration of etching solution and the silicon resistivity on morphology of etched layer was studied. The layers formed on silicon were investigated by scanning electron microscopy (SEM). It was demonstrated that although the deposited Au on silicon is a continuous film, it can produce a layer of silicon nanowires or macropores depending on the used solution concentration. (C) 2009 Elsevier B.V. All rights reserved.