Semiconductor nanopores formed by chemical vapor deposition of heteroepitaxial SiC films on SOI(100) substrates

The authors investigated the formation of nanometer-scale pore (nanopore) arrays by chemical vapor deposition (CVD) of heteroepitaxial SiC films on Si(100) membranes prepared by anisotropic etching of silicon on insulator substrates from the back-side surfaces. SiC heteroepitaxial films with thicknesses of ∼10 nm were grown by pulse jet CVD of CH₃SiH ₃ gas. During the SiC growth, inverted pyramidal pits with {111} facets grew into the Si membranes due to the surface diffusion of Si atoms outward from the bulk Si. Nanopores were formed at the tips of the inverted pyramidal pits. The pore sizes were found to be dependent on the existence of the buried oxide layers under the Si membranes. It is suggested that maintaining the {111} facets during the SiC growth on the Si membrane is essential for smaller size (∼nm) pore formation.