Suppressive effect of Ni–Sn internal electrode at the anode on the leakage current degradation of BaTiO3-based multilayer ceramic capacitors

Abstract

As the BaTiO3 dielectric layer of multi-layer ceramic capacitors (MLCCs) becomes thinner, the problem of leakage current degradation arises. In this study, the leakage current degradation was investigated for the cases when the Ni–Sn internal electrode was placed at either the anode or the cathode. The MLCCs with the Ni–Sn internal electrode at the anode suppressed the leakage current degradation with time significantly better than that at the cathode. The leakage current types for the degraded MLCCs were tunnel and Schottky or Poole–Frenkel for the Ni and Ni–Sn internal electrodes, respectively. High-resolution scanning transmission electron microscopy revealed an interface layer with a high Sn concentration at the interface between the Ni–Sn internal electrode and BaTiO3. Therefore, the interface of the electrode at the anode plays an important role in the leakage current degradation of MLCCs with time.

High DC-Bias Stability and Reliability in BaTiO3-Based Multilayer Ceramic Capacitors: The Role of the Core–Shell Structure and the Electrode

“…Due to the small size of both Ni and BaTiO 3 particles in the Ni220 paste, the printed electrode sheet has less roughness and possesses a flatter electrode/ ceramic interface after lamination, which enables the highquality interface to inhibit the interdiffusion of the elements. The diffusion of Ni elements into the ceramics causes an increase in leakage current in the MLCCs, 36,37 reducing the breakdown voltage and reliability of the devices. The dielectric properties of the MLCCs and the corresponding bulk ceramics are shown in Figure 8.…”

Oxygen vacancy region formation in BaTiO3 adjacent to the interface between the internal electrode and the dielectric layer in Ni–Sn internal electrode multilayer ceramic capacitor exhibiting leakage current suppression

“…HALT was performed on the MLCC with the Ni-Sn and Ni electrodes as the anode and cathode, respectively, compared with the Ni MLCC and Ni-Sn MLCC. 12) Based on the results, the MLCC with the Ni-Sn internal electrode at the anode drastically suppressed the leakage current degradation for a longer time compared with the MLCC with the Ni-Sn internal electrode at the cathode. The leakage current characteristic of the MLCC with the Ni-Sn internal electrode at the cathode was comparable to the leakage current characteristics of the entire Ni MLCC, whereas the leakage current characteristic of the MLCC with the Ni-Sn internal electrode at the anode was comparable to Ni-Sn MLCC leakage current characteristics.…”

“…Sn supposedly trapped oxygen from the dielectric layer BaTiO 3 by oxidation, resulting in its accumulation at the interface. 12) In addition, the oxidation of accumulated Sn inferred oxygen diffusion to Sn from the contacted region of the dielectric layer BaTiO 3 associated with the generation of oxygen vacancies. In other words, the contact between the electrode and the semiconductor BaTiO 3 is resulted from the generation of oxygen vacancies.…”

Atomic-scale Chemical Imaging of Amphoteric Dopant in Ferroelectric BaTiO3

“…High-quality ferroelectric oxide thin films are highly demanding in many device applications over a wide range of thicknesses, including non-volatile random-access memories, high-κ gate dielectrics, and high-end multilayer ceramic capacitors (MLCCs). In the case of MLCCs, as the thickness of the ferroelectric layer decreases with downsizing trend, the effective dielectric constant tends to decrease, and the risk of electrical failure due to leakage current increases, which hampers the development of reliable MLCCs 2,3 . In principle, the leakage current characteristics of a ferroelectric film are governed by the interface with electrode and/or defects within the film, such as grain boundaries, dislocations, and point defects [4][5][6][7][8] .…”