BCT Film Research Articles

Ferroelectric properties of Bi 3.25Ce 0.75Ti 3O 12 thin films prepared by a liquid source misted chemical deposition

Abstract Cerium-substituted bismuth titanate (Bi 3.25 Ce 0.75 Ti 3 O 12 (BCT)) films were deposited on the Pt(111)/SiO 2 /Si(100) substrates by a liquid source misted chemical deposition technique. This film showed X-ray diffraction patterns that crystallization along the (006) direction was suppressed and did not contain any other oxides. The remnant polarization of this film increased with increase in annealing temperature. The 2 P r and 2 E c values of the BCT film annealed at 700 °C were 19.72 μC/cm 2 and 357 kV/cm, respectively. 2 P r value of this film decreased by less than 5% of the initial value after 7 × 10 9 read/write switching cycles at a frequency of 1 MHz.

Structural and ferroelectric properties of (Bi,Ce)4Ti3O12 thin films grown by pulsed laser deposition for ferroelectric random access memories

Abstract The (Bi3.25Ce0.75)Ti3O12 (BCT) thin films with Bi-excess composition were prepared onto Pt/TiO2/SiO2/Si substrates at various temperatures using pulsed laser deposition (PLD) and annealed at various temperatures. The 20 mol% Bi-excess BCT films deposited at 400 °C showed a pure layered structure, the lowest root mean square (rms) roughness, and good ferroelectric properties after annealing at 700 °C in an oxygen ambient. The 70 nm thick-BCT films annealed at 800 °C for 10 min in O2 showed well-saturated P–E curves at an applied electric field of 3 V and a 2Pr of 23 μC/cm2 and a Ec of 180 kV/cm at 5 V. The polarization values were not significantly changed after being subjected to 1.0×1010 switching cycles.

Modulated electron emission for structural characterization of buried layers and interfaces

Abstract Principles and performances of Primary-beam Diffraction Modulated Electron Emission are briefly reviewed. This approach exploits the spatial modulation of the beam electrons waves intensity in ordered atomic arrays, which in turn results in a marked dependence of the electron emission on the incidence angle. Detection of Auger electrons or inelastically backscattered electrons (ionization losses) provides chemical specificity. Surface sensitivity is related to the inelastic mean free path of the detected electrons. Examples are given of the capability of this technique for structural characterization of buried layer and interfaces. They include: i) epitaxial growth of Co oxide on the (001) surface of Co bct film, ii) subsurface behaviour of Co epitaxial layers during the bct→hcp phase transition.