Intrinsic mechanisms of multi-layer ceramic capacitor failure

The major objective of this research is to obtain an improved understanding of degradation mechanisms of MLC capacitors. This is being approached from several directions: (1) Capacitors (mainly Z5U and X7R types) that are new or in various degrees of degradation (as judged by insulation resistance) have been cross sectioned for SEM and optical examination, and for compositional measurements using energy dispersive X-ray analysis (EDAX), Auger electron spectroscopy (AES), and electron beam microprobe. (2) Electrical measurements on similar devices include current-voltage, current-temperature and impedance-frequency. (3) Thermoelectric measurements have been made on non-electroded X7R chips in order to separate the carrier concentration from the drift mobility, and to observe their change following reduction of the ceramic.