Development of temperature-stable thick-film dielectrics. III. Roleof glass on the microstructure evolution of a thick-film dielectric

摘要

[[abstract]]For pt.I see ibid., vol.12, p.798-808 (1989). Glass phase plays an important role in the characteristics of thick-film microelectronics. A dielectric system in BaTiO3 and SrTiO3 containing PbO, B2O3, SiO2, and Al2O 3 glass constituents is investigated. Microstructure evolution and phase distribution after thermal aging are studied with the aid of electron microscope and X-ray diffractometer. It is observed that the phases in 40 vol.% BaTiO3-25 vol.% SrTiO3-35 vol.% glass thick-film dielectric are not altered after 500°C aging for 480 h. The variation in surface morphology after aging is attributed to the precipitation of heavy metal component from the glass which acts as a diffusion species and then dissolves the crystalline phase during firing. The presence of glass in the dielectric enhances the formation of solid solution (BaxSr1-x)TiO3 and results in the broadening of the Curie peak