Influence of Fe-F-co-doping on the dielectric properties of Ba0.6Sr0.4TiO3 thick-films

The influence of Fe acceptor and Fe?F acceptor?donor co-doping on the dielectric response of screen-printed Ba0.6Sr0.4TiO3 thick-films on alumina substrates has been investigated. The Ba0.6Sr0.4TiO3 powders were synthesized by freeze-drying of sols. Permittivity dielectric loss, and tunability were investigated at kHz frequencies with a planar metal-insulator-metal capacitor structure, and at GHz frequencies up to 40 GHz using coplanar waveguide structures. Pure acceptor doping by Fe was found to have a distinct influence on permittivity and dielectric loss-factor at kHz-frequencies and at GHz frequencies due to an internal bias field and pairs of associated defects. Co-doping with F significantly suppresses the influence of the internal bias field and defect-associates at low and microwave frequencies. The commutation quality factor at 10 GHz and E ef

Characterization of non-stoichiometric co-sputtered Ba0.6Sr0.4(Ti1 − x Fe x )1 + x O3 − δ thin films for tunable passive microwave applications

The fabrication of novel iron-doped barium strontium titanate thin films by means of radio frequency (RF) magnetron co-sputtering is shown. Investigations of the elemental composition and the dopant distribution in the thin films obtained by X-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, and time-of-flight secondary ion mass spectroscopy reveal a homogeneous dopant concentration throughout the thin film. The incorporation of the iron dopant and the temperature-dependent evolution of the crystal structure and morphology are analyzed by electron paramagnetic resonance spectroscopy, X-ray diffraction, Raman spectroscopy, atomic force microscopy, and scanning electron microscopy. In summary, these results emphasize the RF magnetron co-sputter process as a versatile way to fabricate doped thin films. Figure Cross section of the RF magnetron co-sputter setup and the X-ray phototelectron spectroscopy iron spectrum of a co-sputtered iron doped Barium strontium titanate thin film Published in the special paper collection on Solid State Analysis (FKA 16) with guest editor G. Friedbacher