Selective formation of luminescent porous silicon by photosynthesis

Abstract

Selective patterning of luminescent porous silicon was achieved by a photosynthesis method. Porous silicon was selectively formed on boron-doped p+ regions patterned on a n-type silicon surface with spatially uniform photoirradiation. Porous silicon stripes formed on 7-μm-wide p+ stripes exhibited a clear visible photoluminescence image with the same dimension. The mechanism of the selective formation is discussed from the viewpoint of how photogenerated holes are accumulated. The resolution limit in the present method is given by the sharpness of the potential distribution at the p-n junctions, i.e., the widths of depletion layers, which reduce for highly doped p-n junctions.