The effects of MoO₃ addition on microwave dielectric properties of Bi₆B₁₀O₂₄ ceramics for ULTCC applications

Microwave ceramic with low‐sintering temperature is one of the most significant classes of materials to realize the multifunction and miniaturization of portable devices. In this paper, Bi₆B₁₀O₂₄ ceramics using the solid-state reaction method are prepared with MoO₃ addition, to achieve both low-temperature sintering and excellent microwave dielectric properties. It is demonstrated that MoO₃ diffuses into the lattice of Bi₆B₁₀O₂₄ to form a solid solution. The higher quality factor (Q × f) of the ceramic is successfully obtained and the temperature coefficient of resonant frequency (τ_f) is adjusted to near zero at the same time without much change in the dielectric constant (ε_r) due to the Mo⁶⁺ incorporation. Compared to Bi₆B₁₀O₂₄ ceramics without addition, the optimum properties of ε_r = 13.9, Q × f = 37,000 GHz, τ_f = − 20 ppm/°C are achieved for Bi₆B₁₀O₂₄ ceramics containing 19 mol% MoO₃. The ceramics are potential candidates for ultra-low temperature co-fired ceramics (ULTCC) applications in wireless communication systems.