Low temperature sintering of ZnTiO_3/TiO_2 based dielectric with controlled temperature coefficient

摘要

Structure, microstructure and dielectric properties of ZnTiO_3 and rutile TiO_2 mixtures (ZnTiO_3 + x TiO_2 with x=0, 0.02, 0.05, 0.1, 0.15 and 0.2) sintered using ZnO-B_2O_3 glass phase (5 wt. percent added) as sintering aid have been investigated. For all compounds, the sintering temperature achieves 900 deg C. The X-ray diffraction patterns indicate for x=0.1 that the material is composed by three phases identified as ZnTiO_3 hexagonal, TiO_2 rutile and ZnO. The presence of ZnO is explained by the introduction of Ti into Zn site to form the (Zn_(1-x)Ti_xTiO_(3+x) solid solution in resulting the departure of ZnO from the ZnTiO_3 structure. The ZnTiO_3+0.15TiO_2 composition sintered at 900 deg C with glass addition exhibits attractive dielectrics properties (epsilon_r = 23, tan(delta) < 10~(-3) and a temperature coefficient of the dielectric constant near zero (tau_(spsilon) = 0 ppm/ deg C)) at 1 MHz. It is also shown that the introduction of TiO_2 allows to tune the temperature coefficient of the permittivity. All these properties lead this system compatible to manufacture silver based electrodes multilayer dielectrics devices.