Dislocations in SrTiO3 thin films grown on LaAlO3 substrates

The dislocation configurations in SrTiO3 thin 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 vector a[100] and line directions of [010]. These dislocations constitute orthogonal arrays of parallel dislocations at the interface, relieving the lattice mismatch between SrTiO3 and LaAlO3. Threading dislocations were found to be the major defects in the films. Two types of threading dislocations with the Burgers vectors a[100] and a[110] were identified. The relations of these threading dislocations with the misfit dislocations were investigated and are discussed in this paper.