Effects of post annealing on the material characteristics and electrical properties of La doped BaTiO3 sputtered films

• Published in: Surface & coatings technology Vol. 202; no. 22-23; pp. 5448 - 5451
• Main Authors: Wu, C.H., Chu, J.P., Wang, S.F., Lin, T.N., Chang, W.Z., John, V.S.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 30.08.2008; Elsevier
• Subjects: Applied sciences; BaTiO3; Cross-disciplinary physics: materials science; rheology; Dielectric constant; Exact sciences and technology; La dopant; Leakage current density; Magnetron sputtering; Materials science; Metals. Metallurgy; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Production techniques; Surface treatment; Surface treatments; XPS; La dopant; Dielectric constant; XPS; Magnetron sputtering; Leakage current density; BaTiO3; Annealing; Electrical properties; Dielectric materials; Doping; Surface treatments; Photoelectron spectroscopy; Heat treatments; Sputtering; Thin films; Magnetrons; Physical vapor deposition; Current density
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2008.06.112

La-doped BaTiO3 thin films with 200 nm thickness were fabricated by r.f. magnetron sputtering system onto Pt/Ti/SiO2/Si substrates. The effects of post-annealing and the amount of dopant on microstructure and electrical properties were studied. The X-ray diffraction (XRD) study reveals that, the film becomes crystallized when the annealing temperature is above 550 °C. In addition, all the films show tetragonal BaTiO3 crystal structure without any second phase or reaction phase formation after annealed at 750 °C. The X-ray photoelectron spectroscopy (XPS) results provide the evidence to support the existence of La2O3 with excess of BaTiO3 structure, when the dopant content reaches more than 1.4 at.%. The dielectric constant also increases with increasing annealing temperature and it may be due to the better crystallinity and larger grain sizes. The 0.1 La film annealed at 750 °C shows a high dielectric constant of 487 measured at 1 MHz. The doped film in the as-deposited condition yields a reduction of leakage current was also observed.