Laser molecular beam epitaxy growth and properties of SrTiO 3 thin films for microelectronic applications

Abstract

Dielectric SrTiO 3 thin films were deposited on LaAlO 3 and Si substrates using laser molecular beam epitaxy. The correlations between the deposition parameters of SrTiO 3 thin films, their structural characteristics, and dielectric properties were studied. The conditions for achieving epitaxial SrTiO 3 thin films were found to be limited to deposition conditions such as deposition temperature. We show that the SrTiO 3 films with single (110) orientation can be grown directly on Si substrates. The nature of epitaxial growth and interfacial structures of the grown films were examined by various techniques, such as Laue diffraction and X-ray photoelectron spectroscopy. The SrTiO 3/Si interface was found to be epitaxially crystallized without any SiO 2 layer. Furthermore, we have measured dielectric properties of the grown SrTiO 3 multilayer suitable for tunable microwave device. A large tunability of 74.7%, comparable to that of SrTiO 3 single-crystal, was observed at cryogenic temperatures. Such STO thin films will be very promising for the development of microelectronic device applications.