Epitaxial growth of high-quality silicon films on double-layer porous silicon

The epitaxial growth of a high-quality silicon layer on double-layer porous silicon by ultra-high vacuum/chemical vapour deposition has been reported. The two-step anodization process results in a double-layer porous silicon structure with a different porosity. This double-layer porous silicon struc ture and an extended low-temperature annealing in a vacuum system was found to be helpful in subsequent silicon epitaxial growth. X-ray diffraction, c ross-sectional transmission electron microscopy and spreading resistance te sting were used in this work to study the properties of epitaxial silicon l ayers grown on the double-layer porous silicon. The results show that the e pitaxial silicon layer is of good crystallinity and the same orientation wi th the silicon substrate and the porous silicon layer.