Laser molecular beam epitaxy growth and properties of SrTiO3 thin films for microelectronic applications

Dielectric SrTiO3thin films were deposited on LaAlO3and Si substrates using laser molecular beam epitaxy. The correlations between the deposition parameters of SrTiO3thin films, their structural characteristics, and dielectric properties were studied. The conditions for achieving epitaxial SrTiO3thin films were found to be limited to deposition conditions such as deposition temperature. We show that the SrTiO3films 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 SrTiO3/Si interface was found to be epitaxially crystallized without any SiO2layer. Furthermore, we have measured dielectric properties of the grown SrTiO3multilayer suitable for tunable microwave device. A large tunability of 74.7%, comparable to that of SrTiO3single-crystal, was observed at cryogenic temperatures. Such STO thin films will be very promising for the development of microelectronic device applications.