A Low-Temperature Route For Producing Epitaxial Perovskite Superlattice Structures On (001)-Oriented Srtio3/Si Substrates

We report on the formation of epitaxial perovskite oxide superlattice structures by atomic layer deposition (ALD), which are integrated monolithically on Si wafers using a template layer of SrTiO3 deposited by hybrid molecular beam epitaxy. ALD film growth was carried out at 360 degrees C, which is significantly lower than the typical deposition temperatures for epitaxial perovskite thin films. The high control over the stacking sequence of different constituents is demonstrated in a series of (BaTiO3)(m)/(SrTiO3)(n) superlattices with various m/n cycle ratios. All superlattice structures were coherently strained to the virtual substrate layer of SrTiO3 on Si. Irrespective of the m/n superlattice sequence, SrTiO3 sublayers retain slight compressive strain which is transmitted to the BaTiO3 layers.