Low-temperature sintering and microwave dielectric properties of B2O3-added ZnO-deficient Zn2GeO4 ceramics for advanced substrate application. Issue 14 (November 2018)

• Record Type: Journal Article
• Authors: Ma, Xing-Hua; Kweon, Sang-Hyo; Im, Mir; Nahm, Sahn
• Is Part Of: Journal of the European Ceramic Society. Volume 38:Issue 14(2018)
• Page Start: 4682
• Page End: 4688
• Publication Date: 2018-11
• Subjects: B2O3 added Zn2-xGeO4-x ceramics -- LTCC -- Microwave dielectric properties -- Advanced ceramic substrates; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2018.06.018
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: ZnO-deficient Zn2- x GeO4- x ceramics with 0.05 ≤ x ≤ 0.15 were synthesized because a ZnO secondary phase is formed in the stoichiometric Zn2 GeO4 ceramics synthesized using micrometer-sized ZnO and GeO2 powders. The Zn1.9 GeO3.9 ceramic sintered at 1000 °C showed a homogeneous Zn2 GeO4 phase with good microwave dielectric properties: εr of 6.8, Q × f of 49, 000 GHz, and τf of −16.7 ppm/°C. However, its sintering temperature was still too high for it to be used as an advanced substrate for low-temperature co-fired ceramic devices. Therefore, various amounts of B2 O3 were added to the Zn1.9 GeO3.9 ceramics to reduce their sintering temperature. Owing to the formation of a B2 O3 -GeO2 liquid phase, these ceramics were well sintered at low temperatures between 925 °C and 950 °C. In particular, 15 mol% B2 O3 -added Zn1.9 GeO3.9 ceramic sintered at 950 °C showed promising microwave dielectric properties for advanced substrates without the reaction with an Ag electrode: εr = 6.9, Q × f = 79, 000 GHz, and τf = −15 ppm/°C.