Low dielectric constant borophosphosilicate glass–ceramics derived from sol–gel process

Abstract

Borophosphosilicate (BPS) glass–ceramics has been synthesized by sol–gel process using boric acid, phosphoric acid and tetraethoxyorthosilicate (TEOS) as starting precursors. The borophosphosilicate glass–ceramics can be sintered below 950 °C in air. The structure of this glass–ceramics was studied by X-ray diffraction (XRD) and scanning electron microscope (SEM), and it was found that the SiO 2 glass phase wraps up BPO 4 crystallites. Si 3(PO 4) 4 crystallites exist when the SiO 2 content is decreased. Between 400 and 950 °C, the liquefaction of glass and the crystallization of crystal concur to keep the chip in shape. The size of the BPO 4 crystalline grains is about 100 nm. The measurements for the dielectric properties of the sintered glass–ceramics show a dielectric constant of less than 5 and a dielectric loss factor of less than 3×10 −3. The glass–ceramics show good potential for its use as dielectric materials in super high frequency multi-layer chip inductors (MLCI).