Dielectric properties of BaTiO3 (BTO)-CaCu3Ti4O12 (CCTO) composite screen-printed thick films for high dielectric constant devices in the medium frequency (MF) range

In this paper, we will study the effect of the presence of CCTO (CaCu3Ti4O12) in the dielectric permittivity and loss of barium titanate (BTO-BaTiO3) thick films. These films were prepared in two layers geometry using the screen printing technique on Al2O3 substrates. Mechanical alloying followed by the solid state procedure has been used successfully to produce powders of CCTO (CaCu3Ti4O12) used in the films. We also look at the effect of the grain size of the BTO and CCTO in the final properties of the film. These samples were studied using X-ray diffraction, scanning electron microscopy (SEM), Raman and infrared spectroscopies. We also did a study of the dielectric permittivity (K) and loss (D) in the medium-frequency (MF) range (100 Hz-1 MHz), of the films. The role played by firing process in the film preparation and the crystallite size of CCTO and BTO in the dielectric constant and structural properties of the films are discussed. Therefore, these measurements confirm the potential use of such materials for small high dielectric planar devices. These films are also attractive for capacitor applications and certainly for microelectronics, microwave devices (cell mobile phones, for example), where the miniaturization of the devices is crucial. (C) 2004 Elsevier B.V. All rights reserved.