Characterization of roughness and defects at an Si/SiO₂ interface formed by lateral solid phase epitaxy using high-resolution electron microscopy

Using high-resolution transmission electron microscopy, we have characterized on an atomic scale the interfacial roughness and the interfacial defects at the Si/SiO₂ interface obtained by lateral solid phase epitaxial growth of Si on SiO₂. At the matrix/SiO₂ interface, the protrusions of Si with 2-3 Si(200) lattice planes make the interface indented. These images can be explained by the pyramid-type or edge-type pseudo Si(100)/SiO₂ interface models composed of small {111} facets. Defects, mainly microtwins, are localized only within 50 nm from the interface, and are adjacent to the SiO₂. It indicates that microtwins are interface-related and are supposed to form from atomic scale indents of the original a-Si/SiO₂ interface.