Solution growth of epitaxial semiconductor-on-insulator layers

Abstract

We have grown defect-free semiconductor-on-insulator (SOI) layers by liquid phase epitaxy. Defect-free Si layers grow laterally over SiO2 by starting from seeding windows or ridge seeds on selectively oxide-masked (111) Si substrates. Growth is terminated when {111} facets at the sidewalls develop. The thin SOI layers are slightly bent in relation to the substrate and adhere firmly to the oxide film. The surface of defect-free SOI layers is formed by a perfect (111) facet, whereas monoatomic steps are found at the interfacial bottom of the layers. Although the Si layers are slightly bent, layers grown from different seeds may coalesce defect-free with seams of up to 150 μm in length. In SiGe layers on patterned Si substrates misfit and threading dislocations promote vertical growth of relaxed layers; SiGe layers grown laterally over oxide-covered Si substrates contain only few dislocations.