Copper displacement deposition on nanostructured porous silicon

Immersion displacement technique innovated by introducing of hydrofluoric acid in solution for Cu deposition was used to decorate porous silicon with Cu. Porous silicon surface was found to be covered by Cu nanosized crystals. Simultaneously porous silicon skeleton was observed to dissolute during Cu solution immersion step. Principally different nanosized objects from porous silicon covered with separated or coalesced Cu nanoparticles to porous Cu membranes were formed. It was found variation of porous silicon preparation regimes allows creating both the rectifying and the ohmic Cu/porous silicon contacts. Crystallographic orientation of the initial Si and porous silicon porosity were revealed to strongly effect on conductivity of Cu films. Finally free standing porous silicon layer was converted into flexible porous Cu membrane by displacement method. Thickness of Cu membrane reached to 25 μm and its electrical conductivity was equal to 60-70% of bulk Cu.