Dislocations in SrTiO₃thin films grown on LaAlO₃substrates

The dislocation configurations in SrTiO₃thin films grown epitaxially on LaAlO₃(100) substrates were studied by conventional and high-resolution transmission electron microscopy. Misfit dislocations had, in most cases, a Burgers vectora〈100〉 and line directions of 〈100〉 These dislocations constitute orthogonal arrays of parallel dislocations at the interface, relieving the lattice mismatch between SrTiO₃and LaAlO₃. Threading dislocations were found to be the major defects in the films. Two types of threading dislocations with the Burgers vectorsa〈100〉?anda〈100〉?were identified. The relations of these threading dislocations with the misfit dislocations were investigated and are discussed in this paper.