Epitaxial oxides on silicon grown by molecular beam epitaxy

Using molecular beam epitaxy, thin films of perovskite-type oxide SrxBa1-xTiO3 (0 less than or equal tox less than or equal to1) have been grown epitaxially on Si(001) substrates. Growth parameters were determined using reflection high energy electron diffraction (RHEED). Observation of RHEED during growth and X-ray diffraction analysis indicates that high quality heteroepitaxy on Si takes place with SrxB1-xTiO3(001)//Si(001) and SrxBa1-xTiO3[010]//Si[110]. Extensive atomic simulations have also been carried out to understand the interface structure and give some insights into the initial growth mechanism of the oxide layers on silicon. SrTiO3 layers grown directly on Si were used as the Sate dielectric for the fabrication of MOSFET devices. An effective oxide thickness < 10 Angstrom has been obtained for a 110 Angstrom thick SrTiO3 dielectric film with interface state density around 6.4 x 10(10)/cm(2)/eV, and the inversion layer carrier mobilities of 220 and 62 cm(2)/V/s for NMOS and PMOS devices, respectively. (C) 2001 Elsevier Science B.V. All rights reserved.