Rinsing and drying studies of porous silicon by high resolution X-ray diffraction

The remarkable single-crystal property of p(+)-type porous silicon (PS) is used to investigate, with high resolution X-ray diffraction, the effects of silicon crystal transfer from wet to dry state: these effects are emphasiz ed by the porous silicon's large specific area. The transfer of silicon fro m a hydrofluoric acid solution to air via a rinsing stage in water is of fu ndamental and technological interests as it occurs in most of chemical trea tments of silicon. First, during drying, a contraction of the PS layer is o bserved, related to the change of surface chemistry, in addition with some reversible deformation. Second, the rinsing stage in water leads to differe nt behavior depending on the rinsing duration: short rinsing stage reduces the strong elongation observed on unrinsed PS while long rinsing stage lead s to non-homogeneous strains in the PS layer. (C) 2001 Elsevier Science Ltd . All rights reserved.