Physical and dielectric properties of BaTiO3–fluoride–glass systems for nitrogen-fireable embedded capacitors

Abstract

BaTiO 3 -based dielectrics containing the selective additive combinations from Pb-free glasses and fluoride compounds such as AlF 3 , BaF 2 , CaF 2 , LiF and ZnF 2 were studied mainly for a potential N 2 -fireable embedded capacitor in printed circuit board with Cu metallization. The physical and dielectric properties, such as dielectric constant (k), loss tangent (tanδ) and T c , strongly depended on the choice of additive combination. A bismuth borosilicate glass was most promising in terms of the degree of densification and dielectric constant. The samples containing LiF and ZnF 2 and sintered at 950°C looked most beneficial in that these additives produced high k of >1,200 and low tanδ of < 0.022 at room temperature regardless of sintering atmosphere. As an example, the 95BaTiO 3 -2LiF-3(Bi borosilicate) sample exhibited k~1,340 and tanδ0.022 at room temperature when fired at 950°C in N 2 .

Giant dielectric constant and tunable phase‐transition characteristics of ZnF2/BaF2‐modified BaTiO3 thick films

“…Our previous report suggested that various fluorides such as AlF 3 , BaF 2 , CaF 2 , LiF, and ZnF 2 even with a small content <3 wt% induced significant changes in dielectric constant of BaTiO 3 thick films with variable Curie temperature . For example, a 2 wt% BaF 2 additive resulted in an enhanced ε r of 967 at 1 MHz at room temperature while 2 wt% ZnF 2 exhibited a corresponding ε r value of 1238 when both the samples were fired at 950°C in N 2 atmosphere . Here, we suggest an even better performance in relative permittivity, which ranges from 1400 up to 1900 at room temperature, as a result of combining the double additives of ZnF 2 and BaF 2 in certain ratios.…”

“…A plot of the variation in Curie temperature as a function of the relative content of BaF 2 is seen in Figure . The reported T c values of −19 and 84°C for the respective 2 wt% ZnF 2 and 2 wt% BaF 2 sample were used for the plot . The T c value gradually increased with the content of BaF 2 .…”

“…This work proposes a specific additive system consisting of ZnF 2 and BaF 2 with a low softening point‐glass for the BaTiO 3 ‐based thick film capacitors on Cu foils, which is potentially for the embedded PCB applications. Our previous report suggested that various fluorides such as AlF 3 , BaF 2 , CaF 2 , LiF, and ZnF 2 even with a small content <3 wt% induced significant changes in dielectric constant of BaTiO 3 thick films with variable Curie temperature . For example, a 2 wt% BaF 2 additive resulted in an enhanced ε r of 967 at 1 MHz at room temperature while 2 wt% ZnF 2 exhibited a corresponding ε r value of 1238 when both the samples were fired at 950°C in N 2 atmosphere .…”

Preparation and characterization of carbonyl iron/glass composite absorber as matched load for isolator

“…Some investigations have indicated that microwave absorbing materials employing CIP as an absorbent showed promising microwave absorbing properties due to its high permeability and Snoek's limit. Low melting point glass (LMPG) has been used as a matrix and high temperature adhesive bonding to prepare many composites, such as glass/BaTiO 3 [23,24], glass/ZnAl 2 O 4 [25] and glass/Co 2 Z ferrite [26,27], because of its capability of melting at a relatively low temperature. The aim of this work is to prepare the 40 vol% carbonyl iron/glass composite absorber using LMPG as the matrix and CIP as the filler.…”