Effect of phosphorus on the structural nonhomogeneity and dielectric properties of alkaline earth aluminoborosilicate glasses

MY Yang and CY Chen and R Yang and Q Zu and SX Huang and Y Zhang and HD Zeng, JOURNAL OF NON-CRYSTALLINE SOLIDS, 657, 123503 (2025).

DOI: 10.1016/j.jnoncrysol.2025.123503

Alkaline earth borosilicate glass with excellent dielectric properties and matching coefficient of thermal expansion is a promising material for glass core substrates. It is vital to understand the effect of P2O5 on the network structure and dielectronic properties of alkaline earth aluminoborosilicate glasses (nP(2)O(5)-(1-n)9.4CaO-4.9MgO-11.6Al(2)O(3)-21.7B(2)O(3)-52.5SiO(2) mol%, n = 0-0.06) for development of the next generation of dielectric glass substrates for electronics. Interestingly, our data indicate that when P2O5 < 3 mol%, both the dielectric constant (epsilon(r)) and dielectric loss (tan delta) decrease, whereas both epsilon(r) and tan delta increase with P2O5 > 3 mol%. These results suggest that the moderate loading of P2O5 induces inhomogeneity in the network, ultimately leading to changes in the trends of both the dielectric constant and dielectric loss in the system. The former results in the inhomogeneity of silicate network structure due to the formation of P-O- Al bonds, while the latter results in loose structure due to the appearance of pyrophosphate structure. The sample with 3 mol% P2O5 exhibits optimal dielectric properties, epsilon(r) 4.10 and tan delta 1.60 x 10(-4) at 1MHz, CTE 3.4 x 10(-6) K-1 at 300K matching with the silicon wafer, plus excellent VH 567 kgf/mm(2). The thermal expansion coefficient and microhardness are mainly affected by the oxygen environment in the glass network. Our research provides a theoretical basis for the development of low-dielectric glasses.

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