Characterization of niobium-doped lead titanate thin films

• Published in: Japanese Journal of Applied Physics 1996-09, Vol.35 (9B), p.4995-4998
• Main Authors: IBRAHIM, R. C, SAKAI, T, NISHIDA, T, HORIUCHI, T, SHIOSAKI, T, MATSUSHIGE, K
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Dielectric properties of solids and liquids; Dielectric, piezoelectric, ferroelectric and antiferroelectric materials; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Niobates, titanates, tantalates, pzt ceramics, etc; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/jjap.35.4995

Lead titanate ( PbTiO 3 ) thin films were deposited on silicon substrates covered with platinum by reactive sputtering using a single multicomponent-type target at high temperatures (around 500° C). Small chips of metallic niobium were incorporated into the target for doping purposes. Samples analyzed in this study were fabricated in such a way that the molar concentration of niobium was kept at 0, 1, 2, 3, or 4%. X-ray diffraction (XRD) patterns showed that samples doped with niobium tended to exhibit epitaxial growth on top of a (111)-oriented platinum electrode. At 2 mol% niobium doping, the tetragonality ratio ( c / a ) exhibited a maximum value and the dielectric permittivity showed a local minimum. The dielectric loss and leakage current characteristics of Nb-doped films were considerably improved. Electric displacement-electric field ( D - E ) hysteresis loops were observed at all doping concentrations. Some promising acoustic surface wave characteristics were also observed. Samples with 1 or 2 mol%Nb seem to be very promising candidates for integrated devices.