Thick-film capacitors prepared from sol-gel derived barium titanate glass-ceramics

Ba-Ti based glass-ceramics with the addition of B and Al elements were synthesized using the sol-gel method. Small BaTiO3 crystallites were precipitated out from the precursor gels in the firing process. The average particle size of the pyrolysed BaTiO3 glass-ceramic powders was in the submicrometer range. Due to the nature of glass-ceramics, the dielectric pastes were prepared directly by blending the, powders with an organic vehicle without. the conventional addition of the glass frit. BaTiO3 thick-films were fabricated using the screen-printing technology. The structural features, dielectric and ferroelectric properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrical measurements. Experimental results showed that a substantial amount of BaTiO3 phase was well developed during the thick-film sintering process and the BaTiO3 grains were homogeneously mixed with the remnant glass phase in the glass-ceramics. Such thick-films have high dielectric constant, low dielectric loss, low leakage current and slim ferroelectric hysteresis loops. And therefore, they are very suitable for the capacitor application. The relationship between the structure and electrical properties is discussed.