Microwave measurement of the dielectric constant of Sr0.5Ba0.5TiO3 ferroelectric thin films

Abstract

Measurement of the relative dielectric constant of a Sr0.5Ba0.5TiO3 (SBT) thin film is presented as a function of electric field strength and temperature over a broad frequency range using a microstrip transmission line. The transmission line was fabricated from a trilayer structure where the SBT film, grown by pulsed laser deposition, was bounded by silver and platinum metallization layers. Such structures involving ferroelectric films could be useful for microwave applications because of the substantially smaller bias voltages (≊1–10 V) compared to those required for bulk material. The SBT film was found to exhibit a dielectric constant of ≊120–250 and a large electric field modulation of ≊50% at 200 kV/cm. These properties of the material as well as the Curie temperature are compared to those of bulk SBT.

Effect of (Ba+Sr/Ti) ratio on the dielectric properties for highly (111) oriented (Ba,Sr)TiO3 thin films

“…The perovskite thin film of (Ba,Sr)TiO 3 (BST) exhibits high relative dielectric constant, low dielectric dissipation factor, low leakage current, and strong tunability under an external dc electric field [1,2]. These properties make it a promising candidate for various microelectronic and optoelectronic applications.…”

Characteristics of (Pb,Sr)TiO3 thin films with various Sr content

“…Ferroelectric thin films have received much attention during the past years for the applications in ferroelectric random access memories (FeRAM), dynamic random access memories (DRAM) and tunable devices due to their large spontaneous polarization and excellent dielectric properties [1][2][3]. Lead titanate (PbTiO 3 ), which has a large spontaneous polarization and a relative small dielectric constant, is a classic ferroelectric material.…”

Epitaxial growth of ferroelectric Ba1−xSrxTiO3thin films for room temperature tunable microwave devices

“…4 to 0. 6 have demonstrated a large electric field effect at room te~nperature.~~ It is well known that the magnitude of the dielectric constant, which changes as a function of the applied electric field, and the dielectric loss at microwave frequencies are the two most important parameters that affect practical applications of the BSTO thin films in tunable microwave devices.…”