Phase analysis and microwave dielectric properties of LTCC TiO2 with glass system

Glass–ceramic composites containing TiO2 (anatase, rutile) and modified borosilicate glasses were prepared and their sintering behaviour, phase evolution, interface reactions, and microwave dielectric properties were investigated as new candidates for low-temperature cofired ceramic (LTCC) materials. It was found that the addition of small amounts of borosilicate glasses lowered the sintering temperature of TiO2 from 1400 to 900 °C. X-ray diffraction results showed that second phases, including Zn2SiO4, were formed when TiO2+zinc-borosilicate glass was used, while no crystalline phase except rutile could be found using unmodified borosilicate glass. High-density TiO2+zinc borosilicate glass material showed promising microwave dielectric properties: relative dielectric constant (εr)=74, quality factor (Q×f)=8000 GHz, and temperature coefficient of resonant frequency (τf)=340 ppm/°C. The effect of borosilicate glasses on the anatase–rutile phase transition was also investigated.