Middle-permittivity LTCC dielectric compositions with adjustable temperature coefficient

Abstract

Middle-permittivity low-temperature co-fired ceramics (LTCC) dielectric compositions with adjustable temperature coefficient have been studied based on CaZrO 3–CaTiO 3. To lower the densification temperature from 1450 °C to less than 900 °C, a series of lithium–borosilicate glass system was designed and added to the CaZrO 3–CaTiO 3 system. As the τ f of glass frits and CaZrO 3 are slightly negative (−5 to −200 ppm/°C) and that of CaTiO 3 is significantly positive, zero τ f could be realized by mixing an appropriate amount of CaTiO 3 (10–20 wt.%) with CaZrO 3. Microstructures, physical properties, and microwave dielectric properties were measured as a function of the compositional ratio of CaZrO 3–CaTiO 3. Nearly zero τ f, together with an acceptable microwave quality factor, was obtained at the composition of CaZrO 3/CaTiO 3/frit=70:15:15 wt.%.