Microwave dielectric properties of BaO-ZnO-B2O3-P2O5 glass-ceramic for LTCC application

A new 10BaO-40ZnO-15B(2)O(3)-35P(2)O(5) (wt%) glass-ceramic with ultra-low permittivity and excellent thermal stability were fabricated by solid-state reaction method. The sintering, phase composition, microstructure and microwave dielectric properties of the glass-ceramics were studied through XRD, SEM, density and dielectric property measurement. The result shows BaZn2(PO4)(2) precipitates first at low sintering temperature of 550 degrees C, and with increasing sintering temperature, Zn-3(PO4)(2) and Zn-3(BO3)(2) phases come out in succession in the glass. The bulk densities of the glass-ceramics firstly increase and then decrease with the increment of firing temperature and the highest density can be achieved at 700 degrees C. The glass-ceramics sintered at 700 degrees C for 2.5 h possesses the optimal dielectric properties of epsilon(r) = 4.16, Q x f = 12,250 GHz (13.6 GHz), and tau(f) = - 1.5 ppm/degrees C. Moreover, the samples have good chemical compatibility with silver electrodes, which indicates that the developed glass-ceramic materials are suitable for LTCC applications.