Direct inkjet printing of composite thin barium strontium titanate films

• Published in: Journal of materials research Vol. 18; no. 12; pp. 2820 - 2825
• Main Authors: Kaydanova, T., Miedaner, A., Curtis, C., Alleman, J., Perkins, J.D., Ginley, D.S., Sengupta, L., Zhang, X., He, S., Chiu, L.
• Format: Journal Article
• Language: English
• Published: New York, USA Cambridge University Press 01.12.2003
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/JMR.2003.0393

Composite Ba0.6Sr0.4TiO3/MgO thin films with 60% tuning and tan [H9254] of 0.007 at 2 GHz were deposited using metal organic decomposition inks by spin coating on single crystal MgO substrates. The films with approximately 1 mol% MgO in Ba0.6Sr0.4TiO3 had a better tuning/loss ratio than either the 0 or the 10 mol% MgO substituted films. Crystalline Ba0.5Sr0.5TiO3 films were produced on both MgO and alumina substrates by inkjet printing of metalorganic precursors with subsequent thermal decomposition followed by annealing at 900°C. Barium strontium titanate lines as narrow as 100 μm were printed on the alumina substrates. The inkjet-printed films were predominantly (100) oriented on MgO and (110) oriented on alumina. The crystalline quality of the inkjet-printed films was improved by annealing at 1100°C for 3 h in oxygen. Both the printed and the spin-coated films had smooth surfaces (300 Å root-mean-square roughness) as required for subsequent deposition of high-resolution metal electrodes. An inkjet-printed Ba0.5Sr0.5TiO3 film (3500 Å) on MgO annealed at 1100°C had 20% tunability of the dielectric constant (ε) at 9.1 V/μm direct current bias and tan δ < 0.002 at 1 MHz.