Direct observation of cross sectional local conductive paths in a degraded multilayered ceramic capacitor

Abstract

Using scanning spreading resistance microscopy, we obtained images of local conduction paths on the cross section of a multilayer ceramic capacitor (MLCC) just before electrical breakdown. The images were observed after the local low-resistance part in the MLCC was identified as being degraded according to the highly accelerated lifetime test. Each grain in the conductive path images was clearly visible, and the insulation resistance (IR) around the cathode was lower than that near the anode. It was concluded that this is a phenomenon that accompanies the migration of oxygen vacancies. We directly observed the degraded resistance distribution of ceramic grains, which showed the bulk-limited conduction mechanism formed by IR degradation.

Synchrotron X‐ray multiscale tomography: Visualization of heterogeneous microstructures and defects in ceramics

“…The degradation of insulation resistance occurs locally from the cathode where the local thickness of the dielectric layer is slightly thinner. 104 Local electric field concentration is found near electrode roughness, discontinuity, and pores. 105 The multilayer structures are unstable under internal stresses arising from differential shrinkage during co-sintering.…”

Direct Observation of Local Dielectric Conductive Paths and Their Dynamics in the Degraded Multilayer Ceramic Capacitors

“…[ 8–14 ] In MLCCs, previous macroscopic measurements have clearly demonstrated the role of oxygen vacancies in the degradation failure of MLCCs; recent work turns to scanning probe microscopy for understanding local insulation resistance degradation of MLCCs, especially Kelvin probe force microscopy, which can give high‐spatial‐resolution surface potential measurements, providing information about the electric field concentrated distribution of degraded dielectric layers. [ 15–24 ] However, for the dielectric breakdown conductive path and its dynamics under electric fields, it is still in the frame of theoretical modeling process, and few studies have been done in the direct imaging of the local conductive path, [ 25 ] and their dynamics in response to the loading fields, which gives a great limitation to understanding local degradation mechanism for MLCCs’ failure. [ 26–28 ]…”

“…[8][9][10][11][12][13][14] In MLCCs, previous macroscopic measurements have clearly demonstrated the role of oxygen vacancies in the degradation failure of MLCCs; recent work turns to scanning probe microscopy for understanding local insulation resistance degradation of MLCCs, especially Kelvin probe force microscopy, which can give high-spatial-resolution surface potential measurements, providing information about the electric field concentrated distribution of degraded dielectric layers. [15][16][17][18][19][20][21][22][23][24] However, for the dielectric breakdown conductive path and its dynamics under electric fields, it is still in the frame of theoretical modeling process, and few studies have been done in the direct imaging of the local conductive path, [25] and their dynamics in response to the loading fields, which gives a great limitation to understanding local degradation mechanism for MLCCs' failure. [26][27][28] Here, considering the difference of thermal conductivity between local dielectric layer (lower thermal conductive, insulatelike phase) and local conductive path (higher thermal conductive, metal-like phase), we proposed scanning thermal microscopy, a powerful tool for local thermal physics characterization, [29][30][31][32][33][34][35][36] to perform direct imaging of the degraded MLCCs by the highly accelerated life test (HALT) method, and successfully obtained local dielectric conductive paths and their electrical tree dynamic behaviors under the dc bias on and off state.…”

Highly Reliable BaTiO3‐Polyphenylene Oxide Nanocomposite Dielectrics via Cold Sintering

“…The incompatibility between polymers and ceramics leads to poor dispersion degree of polymers in the matrix. Since the breakdown happens at the weakest point, [ 31,32 ] homogeneous distribution of polymers is a primary requirement to achieve highly reliable materials. Typically, for the conventional polymer‐BaTiO 3 composites, there have been several researches on the interface design to improve the compatibility between them.…”