A systematic study is undertaken on the effect of growth conditions, on the microstructure and other properties of radio frequency (RF) magnetron sputter deposited SrBi2Ta2O9 (SBT) and SrBi2TaNbO9 (SBTN) films. Polycrystalline SBT and SBTN films were deposited on Si (100), platinized Si, and MgO substrates using stoichiometric targets. Cross sectional scanning electron microscopy reveals the tendency for columnar growth in the films deposited at high substrate temperatures and at high partial pressures of sputtering gas mixtures. AFM studies show that the grain size and the homogeneous surface morphology depends on the post annealing time. XPS studies reveal that oxygen vacancies lie in the Bi2O2 planes. The compositional dependence of the rigid-sublattice mode and the symmetric stretching mode of oxygen octahedrons in the Raman spectra of these materials have been discussed.

The effect of growth conditions such as substrate temperature and oxygen partial pressure on the microstructure and properties of pulsed laser deposited SBTN thin films on Si(100) and MgO(100) substrates have been studied. Crystallization of films begins at room temperature but, the obtained phase was non-ferroelectric. The influence of oxygen pressure (150 to 450 mTorr) on crystallinity of the films deposited on Si(100) at 750°C is negligible. XPS studies of as-deposited films reveal that the oxygen vacancies are preferably present near the Bi ions at the Bi2O2 layers and vary with substrate temperature and oxygen partial pressure. Also, XPS studies of Sr 3d core level for SBTN films suggest that the oxygen ions in the Sr(Ta/Nb)2O7 perovskite layers are much more stable than those in the Bi2O2 layers. Micro-Raman studies of SBTN films deposited below 700°C show Raman modes of a non -ferroelectric phase.

Abstract The growth, microstructure and micro-Raman properties of SrBi2Tao0.8Nb1.2O9 (SBTN) thin films deposited on Si(100) substrates using pulsed laser deposition (PLD) technique were studied at various substrate temperatures. Films were characterized using X-ray diffraction(XRD), atomic force microscopy(AFM), energy dispersive X-ray analysis (EDAX) and micro-Raman studies. AFM studies indicated that the average grain size of the films increased between 0.08 μm to 0.1 μm with the increasing growth temperatures. Micro-Raman studies of SBTN films revealed the fact that shifting of Raman modes corresponds to the BO6 (where B' Ta/Nb) octahedral symmetry, to higher frequencies, is in accordance with the different masses of the B site atoms and the force constants involved due to Nb doping at Ta sites.

Single phase, (001) oriented SrBi2Ta2O9(SBT) thin films have been deposited on (100) MgO substrates using pulsed laser deposition(PLD) technique. In order to study the influence of the growth conditions on the microstructure and stoichiometry, SBT film growth was carried out under different deposition conditions, using an Kr:F excimer laser (248 nm, 30 ns FWHM). Effect of laser fluence(0.75-2 J/cm2), frequency of the laser pulse (4-10 Hz), substrate temperature (700-850°C), oxygen partial pressure(150-450 mTorr) have been studied using X-ray diff-raction(XRD), Scanning Electron Microscope(SEM), X-ray energy dispersive analysis (EDAX), atomic force microscopy(AFM). It was found that small variation in growth temperature and oxygen pressure has a large influence on the average grain size (50-180 nm) and surface roughness (0.14-0.3 nm) respectively. Outgrowths on the film surface were observed at high substrate temperatures, high laser energy and with higher frequencies (>6) of the laser pulse. Highly c-axis oriented SBT thin films with homogeneous surface morphology and with an average surface roughness of 0.14 nm were deposited at 750 °C, 260 mTorr O2 pressure and 1.25 J/cm2 laser fluence. These films have a tangent loss around 0.05 and dielectric constant around 417 with a tunability of 4% in the microwave frequency region (1-20 GHz).

PbTiO3 thin films have been prepared on Si <100> and MgO <100> substrates using sequential RF magnetron sputtering of Pb and Ti targets. As deposited films were post annealed in the presence of oxygen to get PbTiO3 phase. Films were characterized using Xrd, SEM, XPS and temperature dependent Micro-Raman studies. Micro-Raman spectra were obtained from 75K to 550K. We have investigated the low temperature phase transitions and noticed that there is a possible evidence for the structural phase transitions in our low temperature Raman data of the polycrystalline PT films.