Dresden 2006 – wissenschaftliches Programm

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DF: Dielektrische Festkörper

DF 1: Internal Symposium “Integrated Electroceramic Functional Structures”

DF 1.1: Hauptvortrag

Montag, 27. März 2006, 09:30–10:10, M{\"U}L Elch

Barium Strontium Titanate Thin Film for RF Applications — •Ulrich Böttger — RWTH Aachen, Insititut für Werkstoffe der Elektrotechnik II, Sommerfeldstr. 24, 52074 Aachen

Ferroelectric thin films are being intensively studied for wireless communication applications in voltage tunable RF and microwave devices. Tunable circuits like phase shifters, filters or matching networks offer the flexibility to adapt to changes in operating conditions, such as frequency, impedance environment or RF drive level. Key issues for the use of ferroelectric materials in such devices are high tunability, low dielectric losses, temperature stability and reliability, even with respect to alternative technologies based on semiconductor varactor diodes or MEMS (micro electro-mechanical systems). Much emphasis has been placed on thin film ferroelectric material barium strontium titanate, Ba_1−xSr_xTiO₃ because of its promising high-frequency dielectric properties and its ability to device integration.

This talk reviews the properties of thin film Ba_1−xSr_xTiO₃ and discuss the potential physical models of the origin of the tunability and of the correlated losses. Further, basic tunable devices are presented. Simulation results and measurements from such circuits are also given.