Moisture induced degradation of multilayer ceramic capacitors

Abstract When both precious metal electrode and base metal electrode (BME) capacitors were subjected to autoclave (121 °C/100% RH) testing for 500 h, it was found that the precious metal capacitors aged according to a well known aging mechanism (average capacitance degraded less than 3% from their starting values), but the BME capacitors degraded to below the −30% specification limit. One hypothesis for this new failure mechanism was that there could be oxidation or corrosion of the nickel plates. Another hypothesis was that the loss of capacitance was due to chemical changes in the barium titanate. This paper presents the evaluation of the two hypotheses and the physics of the degradation mechanism. It is concluded that there are chemical changes in the barium titanate resulting from the interaction of residual point defects from BME manufacturing and humidity in the field. The continuous reduction in capacitor size makes the newer base metal electrode capacitors more vulnerable to moisture degradation than the older generation precious metal capacitors. In addition, standard humidity life testing, such as JESD-22 THB and HAST, will likely not uncover this problem. Therefore, poor reliability due to degradation of base metal electrode multilayer ceramic capacitors may catch manufacturers and consumers by surprise.

[1]  S. Sriram,et al.  SiC electronics , 1996, International Electron Devices Meeting. Technical Digest.

[2]  Rainer Waser,et al.  dc Electrical Degradation of Perovskite-Type Titanates: I, Ceramics , 1990 .

[3]  Hiroshi Kishi,et al.  Base-Metal Electrode-Multilayer Ceramic Capacitors: Past, Present and Future Perspectives , 2003 .

[4]  D. Dimos,et al.  Electronic and Ionic Trapping at Domain Walls in BaTiO3 , 1994 .

[5]  W. Nix,et al.  The Principles of Engineering Materials , 1973 .

[6]  J. P. Remeika,et al.  Effects of Ambient Atmosphere on the Stability of Barium Titanate , 1955 .

[7]  W. P. Mason.  Aging of the Properties of Barium Titanate and Related Ferroelectric Ceramics , 1955 .

[8]  H. Stoker.  Introduction to Chemical Principles , 1983 .

[9]  L. D. Smith.  Decoupling capacitor calculations for CMOS circuits , 1994, Proceedings of 1994 IEEE Electrical Performance of Electronic Packaging.

[10]  N. Browning,et al.  Observation of oxygen vacancy ordering and segregation in perovskite oxides. , 2001, Ultramicroscopy.

[11]  G. Fantozzi,et al.  Anelastic relaxation associated with the motion of domain walls in barium titanate ceramics , 1996, Journal of Materials Science.

[12]  H. Nesbitt,et al.  Thermodynamic stability and kinetics of perovskite dissolution , 1981, Nature.

[13]  Y. Nakano,et al.  Multilayer ceramic capacitors-recent trends , 1996, ISAF '96. Proceedings of the Tenth IEEE International Symposium on Applications of Ferroelectrics.

[14]  T. Takenaka,et al.  Residual Stress of Multilayer Ceramic Capacitors with Ni-Electrodes (Ni-MLCCs) , 2003 .

[15]  Y. Sakabe,et al.  Base-metal electrode capacitors , 2002 .

[16]  N. Nachtrieb,et al.  The chemistry of imperfect crystals , 1973 .

[17]  Daniel N. Donahoe.  Moisture in Multilayer Ceramic Capacitors , 2005 .

[18]  Samuel J. Schneider,et al.  Ceramics and glasses , 1991 .

[19]  G. Fantozzi,et al.  Effect of Oxygen Vacancies on the Motion of Domain Walls in BaTiO3 Ceramics , 2002 .

[20]  Mike Sampson,et al.  COTS Ceramic Chip Capacitors: An Evaluation of the Parts and Assurance Methodologies , 2004 .

[21]  Daniel N. Donahoe,et al.  Failures in Base Metal Electrode (BME) Capacitors , 2003 .

[22]  D. Joy,et al.  Electron holographic study of ferroelectric domain walls , 1992 .

[23]  G. Arlt.  Twinning in ferroelectric and ferroelastic ceramics: stress relief , 1990 .

[24]  A. Atkinson.  Diffusion in Ceramics , 2006 .

[25]  James F. Scott,et al.  Oxygen-vacancy ordering as a fatigue mechanism in perovskite ferroelectrics , 2000 .