Microwave Properties of Thin BSTO Films Based Varactors for High Frequency Applications

• Published in: Integrated ferroelectrics Vol. 55; no. 1; pp. 871 - 876
• Main Authors: Razumov, S. V., Tumarkin, A. V., Gagarin, A. G., Sysa, M. V., Gaidukov, M. M., Mironenko, P. V., Zemtsov, A. V.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 01.01.2003
• Subjects: BaSrTiO; RF magnetron sputtering
• ISSN: 1058-4587; 1607-8489
• DOI: 10.1080/10584580390259326

The influence of film thickness on electrophysical properties of planar varactors based on ion-plasma deposited BaSrTiO 3 films is investigated. Planar capacitors with copper electrodes were used for tunability and loss factor investigation. Microwave parameters of varactors based on BaSrTiO 3 films were measured at (1 ÷ 8) GHz frequency range and (170 ÷ 370) K temperature range. The tunability and loss factor was found to be strongly depended on film thickness. The optimal thickness of BaSrTiO 3 film from high tunability and low loss factor point of view was estimated as 1 μm approximately. Dielectric losses at frequency range (1 ÷ 8) GHz (tan δ ∼0,01 at 1 GHz, tan δ ∼ 0,014 at 8 GHz and zero bias) and high tunability (Cmax/Cmin ∼ 2) at room temperature were observed.