Ferroelectric SrBi 2 Ta 2 O 9 -(Bi 4 Ti 3 ) 1-x Nb x O 12 (x = 0.02) (SBT-BTN) multilayer thin films with various stacking periodicity have been synthesized on Ir/Ti/SiO 2 /Si substrate by metal organic chemical vapor deposition technique (MOCVD). Tributylbismuth [Bi(C 4 H 9 ) 3 ], Strontium-bis[Tantal(pentanethoxy)(2-methoxyethoxid)] [Sr[Ta(OEt) 5 (OC 2 H 4 OMe)] 2 ], Titanium Bis(isopropoxy)bis(1-methoxy-2-methyl-2-propoxide) [Ti(OiPr) 2 (mmp) 2 ] and Niob-ethoxide [Nb(OC 2 H 5 ) 5 ] were selected as precursors. X-ray diffraction patterns show that the multilayer films annealed at 800 o C consist of fully formed perovskite phase with polycrystalline structure and plate-like grains with no crack. The remanent polarization ( ) and coercive field (Ec) are 16.2 μC/cm 2 and 230 kV/cm, respectively, which is much higher, compared to pure SBT film ( = 6.4 μC/cm 2 , Ec = 154 kV/cm). In the films prepared above 700 o C, postannealing increased the capacitor shorting rate; this was attributed to oxidizing of the top iridium layer. In this paper, the dependence of composition variation around stoichiometric on ferroelectric properties in SBT-BTN multilayer films is studied.
KeywordsFerroelectricSBTBTNMOCVDMultilayer
Paz de Araujo, C.A., Cuchiaro, J.D., Mcmillan, L.D., Scott, M.C. and Scott, J.F. (1995) Fatigue-Free Ferroelectric Capacitors with Platinum Electrodes. Letters toNature, 374, 627-629. http://dx.doi.org/10.1038/374627a0
Park, B.H., Kang, B.S., Bu, S.D., Noh, T.W., Lee, J. and Joe, W. (1999) Lanthanum-Substituted Bismuth Titanate for Use in Non-Volatile Memories. Letters to Nature, 401, 682-684. http://dx.doi.org/10.1038/44352
Watanabe, T., Kojima, T, Sakai, T., Funakubo, H., Osada, M., Noguchi, Y. and Miyayama, M. (2002) Large Remanent Polarization of Bi 4 Ti 3 O 12 -Based Thin Films Modified by the Site Engineering Technique. Journal of Applied Physics, 92, 1518-1521. http://dx.doi.org/10.1063/1.1491594
Kojima, T., Sakai, T., Watanabe T., Funakubo, H., Saito, K. and Osada, M. (2002) Large Rmanent Polarization of (Bi,Nd) 4 Ti 3 O 12 Epitaxial Thin Films Grown by Metalorganic Chemical Vapor Deposition. Applied Physics Letters, 80, 2746. http://dx.doi.org/10.1063/1.1468914
Bao, Z.H., Yao, Y.Y., Zhu, J.S. and Wang, Y.N. (2002) Study on Ferroelectric and Dielectric Properties of Niobium Doped Bi 4 Ti 3 O 12 Ceramics and Thin Films Preparedby PLD Method. Materials Letters, 56, 861-866. http://dx.doi.org/10.1016/S0167-577X(02)00628-6
Noguchi, Y. and Miyayama, M. (2001) Large Remanent Polarization of Vanadium-Doped Bi 4 Ti 3 O 12 . Applied Physics Letters, 78, 1903. http://dx.doi.org/10.1063/1.1357215
Shulman, H.S., Testorf, M., Damjanovic, D. and Setter, N.J. (1995) Microstructure, Electrical Conductivity, and Piezoelectric Properties of Bismuth Titanate. Journal of the American Ceramic Society, 79, 3124-3228.. http://dx.doi.org/10.1111/j.1151-2916.1996.tb08086.x
Villegas, M., Caballero, A.C., Moure, C., Duran, P. and Fernandez, J.F. (1999) Factros Affecting The Electrical Conductivity of Donor-Doped Bi 4 Ti 3 O 12 PiezoelectricCeramics. Journal of the American Ceramic Society, 82, 2411-2416. http://dx.doi.org/10.1111/j.1151-2916.1999.tb02098.x
Shibuya, A., Noda, M., Okuyama, M., Fujisawa, H. and Shimizu, M. (2003) Natural-Superlattice-Structured Bi 4 Ti 3 O 12 - SrBi 4 Ti 4 O 15 Ferroelectric Thin Films. Applied Physics Letters, 82, 784. http://dx.doi.org/10.1063/1.1543248
Kikuchi, T., Watanabe, A. and Uchida, K. (1977) A Family of Mixed-Layer Type Bismuth Compounds. Materials Research Bulletin, 12, 299-304. http://dx.doi.org/10.1016/0025-5408(77)90148-9
Noguchi, Y., Miyayama, M. and Kudo, T. (2000) Ferroelectric Properties of Intergrowth Bi 4 Ti 3 O 12 -SrBi 4 Ti 4 O 15 Ceramics. Applied Physics Letters, 77, 3639. http://dx.doi.org/10.1063/1.1328366
Shibuya, A., Noda, M., Okuyama, M. and Saito, K. (2004) Metallic LaTiO 3 /SrTiO 3 Superlattice Films on the SrTiO 3 (100) Surface. Japanese Journal of Applied Physics, 43, 1178-1180. http://dx.doi.org/10.1143/JJAP.43.L1178
Shibuya, A., Ikemori, S., Wu, W.B., Noda, M. and Okuyama, M. (2003) Preparation and Basic Properties of Ferroelectric Thin Films Having a Superlattice Structure of 2 Bi 3 TiNbO 9 Units-1 Bi 4 Ti 3 O 12 Unit. Applied Physics Letters, 83, 1411-1413. http://dx.doi.org/10.1063/1.1604171
Sakamoto, W., Imada, K., Shimura, T. and Yogo, T. (2005) Synthesis and Properties of Intergrown Bi 4 Ti 3 O 12 - SrBi 4 Ti 4 O 15 Ferroelectric Thin Films by Chemical Solution Deposition. Japanese Journal of Applied Physics, 44, 6952- 6956. http://dx.doi.org/10.1143/JJAP.44.6952
Ortega, N., Bhattacharya, P. and Katiyar, R.S. (2006) Enhanced Ferroelectric Properties of Multilayer SrBi 2 Ta 2 O 9 / SrBi 2 Nb 2 O 9 Thinfilms for NVRAM Applications. Materials Science and Engineering B, 130, 36-40. http://dx.doi.org/10.1016/j.mseb.2006.02.006
Hyeon, J.-Y., Lisker, M., Silinskas, M., Burte, E.P. and Edelmann, F.T. (2005) Liquid-Delivery MOCVD of Strontium Bismuth Tantale Thin Films Using Sr[Ta(OC 2 H 5 ) 5 (OCH 2 CH 2 OCH 3 )] 2 and Liquid Bi(CH 2 CH=CH 2 ) 3 as Precursors as Precursors. Chemical Vapor Deposition, 11, 213-218. http://dx.doi.org/10.1002/cvde.200406335
Ritterhaus, Y., Hur’yeva, T., Lisker, M. and Burte, E.P. (2007) Iridium Thin Films Deposited by Liquid Delivery MOCVD Using Ir(EtCp)(1,5-COD) with Toluene Solvent. Chemical Vapor Deposition, 13, 698-704. http://dx.doi.org/10.1002/cvde.200706630
Lisker, M., Hur’yeva, T., Ritterhaus, Y. and Burte, E.P. (2007) Effect of Annealing in Oxygen Atmosphere on Morphological and Electrical Properties of Iridium and Ruthenium Thin Films Prepared by Liquid Delivery MOCVD. Surface and Coatings Technology, 201, 9294-9298. http://dx.doi.org/10.1016/j.surfcoat.2007.04.078
Yang, B., Zhang, X.J. and Zhang, S.T. (2001) Bismuth-Layered-Ferroelectric BI 3 TINBO 9 Thin Films Grown by Pulsed Laser Deposition. Ferroelectrics, 252, 493-500. http://dx.doi.org/10.1080/00150190108016267
Yang, B., Zhang, X.J., Zhang, S.T., Chen, X.Y., Wu, Z.C., Chen, Y.F., Zhu, Y.Y., Liu, Z.G. and Ming, N.B. (2001) In Situ Electrical-Field-Induced Growth and Properties of Bi3TiNbO9 Ferroelectric Thin Films. Applied Physics Letters, 79, 4559. http://dx.doi.org/10.1063/1.1430023
Zhu, J., Zhang, X., Zhu, Y. and Desu, S.B. (1998) Size Effects of 0.8SrBi 2 Ta 2 O 9 -0.2Bi 3 TiNbO 9 Thin Films. Journal of AppliedPhysics, 83, 1610. http://dx.doi.org/10.1063/1.366872
Perez, W., Ching-Prado, E., Dobal, P.S., Reynes-Figueroa, A., Katiyar, R.S., Tirumala, S. and Desu, S.B. (1999) Micro-Raman Study of SrBi 2 Ta 2 O 9 -Bi 3 TiNbO 9 Thin Films. Proceedings of Materials Research Society, 541, 274.
Ching-Prado, E., Pérez, W., Dobal, P.S., Katiyar, R.S., Tirumala, S. and Desu, S.B. (2000) A Structural Study of SrBi 2 Ta 2 O 9 -Bi 3 TiNbO 9 Ferroelectric Thin Films. Proceedings of Materials Research Society, 596, 173. http://dx.doi.org/10.1557/PROC-596-173
Silinskas, M., Lisker, M., Kalkofen, B., Matichyn, S. and Burte, E.P. (2004) Deposition Kinetics of MOCVD of Strontium Bismuth Tantalate Thin Films. Lithuanian Journal of Physics, 44, 375-379. http://dx.doi.org/10.3952/lithjphys.44508
Lisker, M., Silinskas, M., Kalkofen, B. and Burte, E.P. (2005) Liquid-Delivery MOCVD of SBT Thin Films Using Novel Bismuth Precursors. Proceedings of the EUROCVD, Bochum, 5-9 September 2005, 881-888.
Song, C.H., Lia, W., Maa, J., Gua, J., Yaoa, Y.Y., Fenga, Y., Lua, X.M., Zhua, J.S., Wanga, Y.N., Chanb, W.L.H. and Choy, C.L. (2004) Ferroelectric Properties of Bi 3.25-x/3 La 0.75 Ti 3-x Nb x O 12 Films Prepared by Pulsed Laser Deposition. Solid State Communications, 129, 775-780. http://dx.doi.org/10.1016/j.ssc.2003.12.030
Li, Y.B., Zhang, S., Fei, W.D., Gan, Z.H. and Mhaisalkar, S. (2007) Formation and Stability of Pyrochlore in Sputtered SBT Thin Films. Advances in Applied Ceramics, 106, 180-185. http://dx.doi.org/10.1179/174367607X178139
Boyle, T.J., Buchheit, C.D. and Rodriguez, M.A. (1996) Formation of SrBi 2 Ta 2 O 9 —Part I: Synthesis and Characterization of a Novel “Sol-Gel” Solution for Production of Ferroelectric SrBi 2 Ta 2 O 9 Thin Films. Journal of Materials Research, 11, 2274-2281. http://dx.doi.org/10.1557/JMR.1996.0289
Kim, J.K., Kim, J., Song, T.K. and Kim, S.S. (2002) Effects of Niobium Doping on Microstructures and Ferroelectric Properties of Bismuth Titanate Ferroelectric Thin Films. Thin Solid Films, 419, 225-229. http://dx.doi.org/10.1016/S0040-6090(02)00550-3
Lisker, M., Hur’yeva, T., Ritterhaus, Y. and Burte, E.P. (2009) Effect of Annealing in Oxygen Atmosphere on Morphological and Electrical Properties of Iridium and Ruthenium Thin Films Prepared by Liquid Delivery MOCVD. Surface and Coatings Technology, 201, 9294-9298. http://dx.doi.org/10.1016/j.surfcoat.2007.04.078
Ge, S.B., Ning, Z.Y., Dong, Z.G. and Shen, M.R. (2002) Investigation on Dielectric Properties of Polycrystalline BT/ST Multilayer Thin Films. Journal of Physics D: Applied Physics, 35, 906-910. http://dx.doi.org/10.1088/0022-3727/35/9/311