Structural evolution of dislocation half-loops in epitaxial BaTiO3BaTiO3 thin films during high-temperature annealing

Abstract

BaTiO3BaTiO3 thin films were grown on (001) SrTiO3(001) SrTiO3 by reactive molecular beam epitaxy. Transmission electron microscopy studies showed that there is a high density of dislocation half-loops inside 8- and 12-nm12-nm-thick films. By thermal annealing at 1000°C1000°C, the isolated small dislocation half-loops grow and combine to form a self-assembled regular dislocation network at the film/substrate interface. Threading dislocations in the films are removed and the lattice mismatch strain in the film is nearly completely relaxed by annealing at high temperature.