Dielectric microwave characterizations of (Ba,Sr)TiO3 film deposited on high resistivity silicon substrate: Analysis by two-dimensional tangential finite element method

Abstract

( Ba , Sr ) TiO 3 (BST) thin films were deposited on high resistivity silicon substrates by in situ rf magnetron sputtering. A buffer layer was used to improve the cristallinity of the films, the composition was fixed to Ba/Sr=30/70. The relative permittivity and the losses were measured up to 60 GHz using coplanar strip lines. The dispersion of the permittivity and the losses has been determined with a home made numerical code based on finite elements: ELFI. We show that, with the measurements of the scattering parameters coupled with ELFI, it is possible to know the BST complex permittivity over a very broad frequency band. The BST films deposited by in situ (700 °C) present excellent properties between 1 to 60 GHz. The relative permittivity is in the order of 270 and the losses are very small 0.09 at 60 GHz. These structures BST/silicon high resistivity show good potentialities for devices microwaves applications which need future integration in a silicon environment.

Microwave evaluation of Pb0.4Sr0.6TiO3 thin films prepared by magnetron sputtering on silicon: Performance comparison with Ba0.3Sr0.7TiO3 thin films

“…1 Many devices have been intensively studied and fabricated for different applications: tunable microwave devices/radio frequency components and power-supply decoupling. 2,3 Among the various ferroelectric films, BST thin film is the most promising material for micro wave tunable capacitors due to its high dielectric constant, high tunability and its paraelectricity at normal operating temperatures. Although pure BST material presents a large loss factor, typically 10% at 60 GHz, which impacted on the device's figure of merit (FOM).…”

Broadband Dielectric Characterization of Sapphire/TiOx/Ba0.3Sr0.7TiO3 (111)-Oriented Thin Films for the Realization of a Tunable Interdigitated Capacitor

“…This structure, by imposing a 1 μm finger gap between the electrodes, allows application of a static electric field (E max = 300 kV/cm) to extract the tunablity; for such dimensions, the electric field distribution in the gap is assumed to be uniform. additionally, this configuration provides the opportunity for measuring the s-parameters of the structure, which will be considered as input data for the full-wave element analysis [21].…”

Dielectric Properties at Microwaves Frequencies of (Ni, Ti, La, Mg)-Doped Ba0.3Sr0.7TiO3 Thin Films Deposited onHigh-Resistivity Silicon Substrates

“…the substrates were heated during deposition, and as a consequence, the perovskite phase is obtained without postannealing treatment. The growth temperature is set to 800°C; these BST sputtering conditions have been optimized for HRSi substrates 11 and we have used the same conditions for doped BST films. The substrate used in these experiments is HRSi; this substrate is very well suited for future monolithic integration; the film thickness is in the order of 500 nm.…”