X-ray topographic characterization of porous silicon layers

Abstract

X-ray topographic techniques have been used to characterize porous silicon layers obtained by anodic dissolution of silicon single crystals. Porous silicon is found to be a single crystal even for quite thick layers. There is a misorientation between given lattice planes in the porous silicon relative to the corresponding lattice planes in the silicon substrate. The results show that this misorientation depends on the orientation of the lattice planes. The presence of a porous layers always produces an elastic curvature of the sample, the layer being under compression. We show that strong local strains existing at the interface between the porous layer and the substrate can be virtually eliminated by choosing a proper composition of the electrolyte. © 1984.