Growth and properties of highly orientated Sr0.75Ba0.25Nb2O6 thin films on silicon substrates with MgO or TiN buffer layers

Sr0.75Ba0.25Nb2O6 (SBN75) thin films were deposited on silicon substrate with MgO (100) or TiN (100) buffer layer by radio-frequency magnetron sputtering technique. X-ray diffraction confirmed that a 900 °C annealed SBN self-buffer layer introduced before SBN deposition can lead to the highly c-axis orientation of SBN75 thin film on MgO buffer layer. Energy-dispersive spectrometry analysis showed that the SBN75 films had target-film composition transfer and the TiN buffer layer was partially oxidized during SBN growth. The refractive index of SBN films on both MgO/Si and TiN/Si substrates was determined by fitting the measured reflectance curves with Sellmeier dispersion model in the visible region and the micro-structures were studied by scanning electron microscopy. In this paper, the conditions for SBN/MgO/Si treated as waveguide structure were also discussed.