Ferroelectric strontium bismuth tantalate thin films deposited by metalorganic chemical vapour deposition (MOCVD)

Citation
Jf. Roeder et al., Ferroelectric strontium bismuth tantalate thin films deposited by metalorganic chemical vapour deposition (MOCVD), J EUR CERAM, 19(6-7), 1999, pp. 1463-1466
Citations number
9
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
ISSN journal
09552219 → ACNP
Volume
19
Issue
6-7
Year of publication
1999
Pages
1463 - 1466
Database
ISI
SICI code
0955-2219(1999)19:6-7<1463:FSBTTF>2.0.ZU;2-T
Abstract
Thin films of Sr1-xBi2+xTa2O9 (SBT) have been deposited by metalorganic che mical vapor deposition (MOCVD) on 150 mm Si wafers with Pt/Ti electrodes. T he choice of Bi precursor significantly affects the process; film homogenei ty is significantly improved when using a beta-diketonate Bi precursor in c ombination with compatible Sr and Ta precursors. A highly repeatable proces s has been developed, with good run-to-run composition and thickness contro l. Effects of Bi volatility have been investigated in annealing experiments that show the onset of Bi loss at similar to 570 degrees C at reduced pres sure (1-10 Torr). Film properties relevant to integrated ferroelectric rand om access (Fe RAMS) memories have also been characterized. Remenant polariz ations (2P(r)) up to 24 mu C cm(-2) have been obtained at 5 V, with 90% sat uration of 2P(r) at 1.5 V and a coercive voltage of 0.52 V for a 140 mn fil m. Electrical leakage current density values were <2x10(-8) A cm(-2) at 1.5 V. Fatigue endurance has been measured to 10(11) cycles with < 10% degrada tion in switched charge. (C) 1999 Elsevier Science Limited. All rights rese rved.