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Ba0.9Sr0.1TiO3 (BST) thin films were deposited on fused quartz and Pt/TiN/Si3N4/Si substrates by radio frequency magnetron sputtering technique. Microstructure and chemical bonding states of the BST films annealed at 700 °C were characterized by field emission scanning electron microscopy, X-ray photoelectron spectroscopy, glancing angle X-ray diffraction and Raman spectrum. Optical constants including refractive indices, extinction coefficients and bandgap energies of the as-deposited BST film and the BST films annealed at 650, 700 and 750 °C, respectively, were determined from transmittance spectra by envelope method and Tauc relation. Dielectric constant and remnant polarization for the BST films increase with increasing annealing temperature. Leakage current density-applied voltage (J–V) data indicate that the dominant conduction mechanism for all the BST capacitors is the interface-controlled Schottky emission under the conditions of 14 V

Radio frequency magnetron sputtered Ba"0"."6"5Sr"0"."3"5TiO"3 (BST) thin films were etched in CF"4/Ar/O"2 plasma by magnetically enhanced reactive ion etching technique. The etching characteristics of BST films were characterized in terms of microstructure and electrical properties. Atomic force microscopy and X-ray diffraction results indicate that the microstructure of the etched BST film is degraded because of the rugged surface and lowered intensities of BST (100), (110), (111) and (200) peaks compared to the unetched counterparts. Dielectric constant and dielectric dissipation of the unetched, etched and postannealed-after-etched BST film capacitors are 419, 346, 371, 0.018, 0.039 and 0.031 at 100kHz, respectively. The corresponding dielectric tunability, figure of merit and remnant polarization are 19.57%, 11.56%, 17.25%, 10.87, 2.96, 5.56, [email protected]/cm^2, 2.32 and [email protected]/cm^2 at 25V, respectively. The leakage current density of 1.75x10^-^4 A/cm^2 at 15V for the etched BST capacitor is over two orders of magnitude higher than 1.28x10^-^6 A/cm^2 for the unetched capacitor, while leakage current density of the postannealed-after-etched capacitor decreases slightly. It means that the electrical properties of the etched BST film are deteriorated due to the CF"4/Ar/O"2 plasma-induced damage. Furthermore, the damage is alleviated, and the degraded microstructure and electrical properties are partially recovered after the etched BST film is postannealed at 923K for 20min under a flowing O"2 ambience.

Bi1−x Ce x FeO3 (x = 0, 0.05, 0.1, 0.15 and 0.20) (BCFO) thin films were deposited on Pt/TiN/Si3N4/Si substrates by sol–gel technique. Crystal structures, surface chemical compositions and bonding states of BCFO films were investigated by X-ray diffraction and X-ray photoelectron spectroscopy (XPS), respectively. Compared to BiFeO3 (BFO) counterparts, the fitted XPS narrow-scan spectra of Bi 4f7/2, Bi 4f5/2, Fe 2p3/2, Fe 2p1/2 and O 1s peaks for Bi0.8Ce0.2FeO3 film shift towards higher binding energy regions by amounts of 0.33, 0.29, 0.43, 0.58 and 0.49 eV, respectively. Dielectric constants and loss tangents of the BCFO (x = 0, 0.1 and 0.2) film capacitors are 159, 131, 116, 0.048, 0.041 and 0.035 at 1 MHz, respectively. Bi0.8Ce0.2FeO3 film has a higher remnant polarization (P r = 2.04 μC/cm2) than that of the BFO (P r = 1.08 μC/cm2) at 388 kV/cm. Leakage current density of the Bi0.8Ce0.2FeO3 capacitor is 1.47 × 10−4 A/cm2 at 388 kV/cm, which is about two orders of magnitude lower than that of the BFO counterpart. Furthermore, Ce cations are feasibly substituted for Bi3+ in the Bi0.8Ce0.2FeO3 matrix, possibly resulting in the enhanced ferroelectric properties for the decreased grain sizes and the reduced oxygen vacancies.

Ba0.65Sr0.35TiO3 (BST) thin films were deposited on Pt/Ti/SiO2/Si substrates by radio frequency magnetron sputtering technique. X-ray photoelectron spectroscopy (XPS) depth profiling data show that each element component of the BST film possesses a uniform distribution from the outermost surface to subsurface, but obvious Ti-rich is present to BST/Pt interface because Ti4+ cations are partially reduced to form amorphous oxides such as TiOx (x

Bi1−xCexFeO3 (x=0, 0.05, 0.1, 0.15, and 0.20) (BCFO) thin films were deposited on Pt/TiN/Si3N4/Si and fluorine-doped SnO2 glass substrates by sol-gel technique, respectively. The effect of Ce doping on the microstructure, electrical and magnetic properties of BCFO films was studied. Compared to counterparts of BiFeO3 (BFO) film, the fitted Bi 4f7/2, Bi 4f5/2, Fe 2p3/2, Fe 2p1/2, and O 1s peaks for Bi0.8Ce0.2FeO3 film shift toward higher binding energy regions by amounts of 0.33, 0.29, 0.43, 0.58, and 0.49 eV, respectively. Raman redshifts of 2–4 cm−1 and shorter phonon lifetimes for the Bi0.8Ce0.2FeO3 film might be related to anharmonic interactions among Bi–O, Ce–O, (Bi, Ce)–O, and Fe–O bonds in the distorted oxygen octahedron. Compared to the pure counterparts, the dielectric and ferroelectric properties of the Bi0.8Ce0.2FeO3 film are improved due to the decreased oxygen vacancies by the stabilized oxygen octahedron. Current density values for the BFO and Bi0.8Ce0.2FeO3 film capacitors are 9.89×10−4 and...