Ultralow temperature cofired BiZn₂VO₆ dielectric ceramics doped with B₂O₃ and Li₂CO₃ for ULTCC applications

In this paper, BiZn₂VO₆ doped with sintering aids of B₂O₃ and Li₂CO₃ is investigated in order to broaden the options for ultralow temperature cofired ceramics (ULTCC). The sintering behavior, microstructure, and microwave dielectric properties are studied. In combination with 1 wt% B₂O₃ and 5 wt% Li₂CO₃ dopants, the sintering temperature of the BiZn₂VO₆ ceramics was reduced from 780°C to 600°C. The co‐doped BiZn₂VO₆ ceramics exhibited a low relative permittivity (εr) of 8.9 and a quality factor (Q × f) of 13 000 GHz at a microwave‐range frequency of 9 GHz. The temperature coefficient of resonant frequency (τf) was measured to be −97 ppm/°C. The average linear coefficient of thermal expansion (CTE) was 7.2 ppm/°C. With the low sintering temperature, the co‐doped BiZn₂VO₆ ceramics are compatible to be cofired with cost‐effective aluminum electrodes. This was proven in a reaction test between the BiZn₂VO₆‐B₂O₃‐Li₂CO₃ and aluminum powders, in which no chemical interaction could be detected. These promising properties make the B₂O₃‐Li₂CO₃ co‐doped BiZn₂VO₆ an ideal candidate for ULTCC applications.