High permittivity Bi24Fe2O39 thin films prepared by a low temperature process

Abstract

High permittivity Bi24Fe2O39 (BFO) thin films have been deposited on platinized silicon substrates by a low temperature process combining rf magnetron sputtering at room temperature and postdeposition annealing at 450 °C. A nearly pure tetragonal crystal structure with highly (201)-preferred orientation, determined by x-ray diffraction, was formed in the BFO thin film. The BFO film not only exhibits high dielectric permittivity (εr=113) and relatively low loss tangent (tan δ=0.012), but also shows a fairly small quadratic voltage coefficient of capacitance (α∼800 ppm/V2) and a small temperature coefficient of capacitance (αT∼790 ppm/°C). Moreover, the leakage current density, obeying the Fowler–Nordheim tunneling mechanism, remains at a reasonably low level with the increase in applied electric field (J∼10−6–10−4 A/cm2 under E=400 kV/cm). These attractive dielectric and electrical properties make the low temperature processed Bi24Fe2O39 thin film a promising candidate for high-k dielectric applications in silicon-based integrated circuits.

Electrochemical detection of Pb(ii) and Cd(ii) using bismuth ferrite nanoparticle modified carbon paste electrodes

“…Except for small peaks at around 25.4°, 31.5° and 37.7° which are attributed to the BiFeO 3 impurity secondary phase, the diffractive peaks at 28.4°, 33.1°, 46.1°, 47.0°, 56.0°, 58.3°, and 74.5° can be indexed to the (201), (220), (222), (400), (202), (421), (402), (421), and (423) facets of the tetragonal lattice of the Bi 24 Fe 2 O 39 phase, respectively. 43,44 The spacing between the parallel planes of the synthesized crystalline structure of the bismuth ferrite nanoparticle was calculated using the Bragg's equation (eqn (1)) and was found to be in the range of 0.161–0.280 nm. n λ = 2 d sin θ …”

Varistor and Magnetic Properties of Nickel Copper Zinc Niobium Ferrite Doped with Bi2O3

“…t g / t b . The intrinsic relative dielectric constants of the grain‐boundary phases, Bi 25 Fe 2 O 39 , BiFeO 3 , and Bi 2 Fe 4 O 9 , are about 113, 52, and 31, respectively . The effective relative dielectric constant of the specimens from large to small are quenched specimens, furnace‐cooled specimens, and annealed specimens, respectively.…”

High permittivity 0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3 relaxor thin films for high-value, wide-temperature capacitor applications

“…Accordingly, a negative slope is obtained in the ln(J/E 2 ) versus 1/E plot for high electric fields, coherent with a contribution from FN tunneling in the leakage current, i.e., an injection of charge carriers into the PMNT film from electrodes by tunneling through the interfacial energy barrier. 27,28 IV. CONCLUSIONS High permittivity 0.9Pb(Mg 1/3 Nb 2/3 )O 3 -0.1PbTiO 3 relaxor thin films with a nearly pure perovskite structure as well as a dense and uniform microstructure have been prepared on Pb(Zr,Ti)O 3 -buffered platinized silicon substrates by sol-gel method.…”