Base-Metal Electrode-Multilayer Ceramic Capacitors: Past, Present and Future Perspectives

TLDR

Multilayer ceramic capacitors (MLCCs) are the most produced fine‑ceramic product, with 550 billion units and $6 billion in sales worldwide in 2000, and base‑metal electrode (BME) technology has expanded their application range. This review surveys recent advances in Ni‑based BME MLCCs from the perspective of nonreducible dielectric materials. The authors systematically study how intermediate‑ionic‑size rare‑earth ions occupy A‑ and B‑sites in BaTiO₃, affecting electrical properties and microstructure, and relate these to Ni‑MLCC performance. Doped BaTiO₃ with Dy₂O₃, Ho₂O₃, Er₂O₃, or Y₂O₃ yields highly reliable Ni‑MLCCs with sub‑2 µm electrodes, where the rare‑earth ions control donor/acceptor ratios and microstructural evolution, improving electrical performance.

Abstract

Multilayer ceramic capacitor (MLCC) production and sales figures are the highest among fine-ceramic products developed in the past 30 years. The total worldwide production and sales reached 550 billion pieces and 6 billion dollars, respectively in 2000. In the course of progress, the development of base-metal electrode (BME) technology played an important role in expanding the application area. In this review, the recent progress in MLCCs with BME nickel (Ni) electrodes is reviewed from the viewpoint of nonreducible dielectric materials. Using intermediate-ionic-size rare-earth ion (Dy2O3, Ho2O3, Er2O3, Y2O3) doped BaTiO3 (ABO3)-based dielectrics, highly reliable Ni-MLCCs with a very thin layer below 2 µm in thickness have been developed. The effect of site occupancy of rare-earth ions in BaTiO3 on the electrical properties and microstructure of nonreducible dielectrics is studied systematically. It appears that intermediate-ionic-size rare-earth ions occupy both A- and B-sites in the BaTiO3 lattice and effectively control the donor/acceptor dopant ratio and microstructural evolution. The relationship between the electrical properties and the microstructure of Ni-MLCCs is also presented.