Characterization of Silver Interdiffusion into (Zn,Mg)TiO_3+x:Bi:Sb Multilayer Ceramic Capacitor

Abstract

In this study, (Zn,Mg)TiO3+x+Bi2O3+Sb2O5 multilayer ceramic capacitors (MLCCs) with different proportions of a silver (Ag)–palladium (Pd) mixture acting as the inner electrode were sintered at 925°C for 2 h to evaluate the effect of the inner electrode on reliability. The main results reveal that the lifetime is inversely proportional to the Ag content in the Ag/Pd inner electrode. Ag diffusion into the (Zn,Mg)TiO3+x+Bi2O3+Sb2O5 MLCC during cofiring at 925°C for 2 h and Ag migration at 140°C against 200 V are both responsible for the short lifetime of the (Zn,Mg)TiO3+x+Bi2O3+Sb2O5 MLCC, particularly the latter factor. A Bi,Sb‐rich secondary phase was present at the triple junction and a small amount of Ag was detected from the second phase for a (Zn,Mg)TiO3+x+Bi2O3+Sb2O5 MLCC with a high Ag content in the inner electrode of Ag/Pd=99/01. However, this was not the case with a low Ag content in the inner electrode of Ag/Pd=90/10. This means that the Bi,Sb‐rich second phase plays an important role in determining the degradation of insulation resistance due to the excessive formation of oxygen vacancies from the reaction of Ag+ for Bi3+ or Sb5+ substitution to lower the activation energy of the (Zn,Mg)TiO3+Bi2O3+Sb2O5 dielectrics and to enhance markedly the effect of Ag migration.

New Opportunities in Metallization Integration in Cofired Electroceramic Multilayers by the Cold Sintering Process

“…The process is exposed as two firing steps: the binder burnout, which normally take place at around at 500 and 600 °C to remove organics, and the cofiring of ceramic and metallic phase which occurs above 850–1050 °C. There are many studies reporting interdiffusion taking place during firing because the sintering temperature is very close to the melting temperature of metals, especially when cofiring with Ag and Cu, which have melting points of 961 and 1084 °C, respectively. ,, Here, by use of the cold sintering, the LTCC processing is performed at extremely low temperatures below 300 °C, which well below the melting points of Cu, Fe, and Al metals that are used as a metal layers in this study. As depicted in TEM analysis (Figures and )­, the interfaces of ceramic/metal and metal/ceramic are very clear, and no chemical and physical interdiffusions of the adjacent layers are observed.…”

Effect of sintering parameters on silver diffusion of (Zn,Mg)TiO3based multilayer ceramic capacitors

“…It is well known that silver migration into ceramics in the cofiring process of low sintering temperature MLCCs is another important reason that influences the reliability and dielectric characteristics. [14][15][16][17] In this paper, the effects of heating rate and two-step sintering on the sintering behaviour, microstructure and silver diffusion of ZMT MLCC with pure silver electrodes were investigated.…”