DocumentCode :
968177
Title :
Voltage Dependence of Activation Energy for Multilayer Ceramic Capacitors
Author :
Burton, Larry C.
Author_Institution :
Virginia Plytech. Inst. and State Univ., Blacksburg, VA
Volume :
8
Issue :
4
fYear :
1985
fDate :
12/1/1985 12:00:00 AM
Firstpage :
517
Lastpage :
524
Abstract :
Current-voltage and activation energy measurements can be used to probe grain boundary potential barriers. A common type of activation energy for Current conduction in a polycrystalline material is that due to the grain boundary potential barrier. Activation energy can be related directly to grain boundary barrier height. The height of this barrier depends on occupation of grain boundary states. Its decrease with applied voltage accounts for the superohmic current-voltage behavior of polycrystalline silicon and of ZnO varistors. It also accounts for positive temperature coefficient device behavior. A similar voltage dependence is reported here for barrier layer and COG type capacitors, where activation energies decrease from 0.99 to 0.44 eV and from 1.61 to 0.90 eV, respectively. Such decreases are not seen for X7R devices, even though currents are superohmic. Several mechanisms account for this. It is concluded that the grain boundary potential barrier may offer a major source of impedance to leakage current in multilayer ceramic capacitors, and its decrease may result in device failure.
Keywords :
Ceramic capacitors; Capacitors; Ceramics; Conducting materials; Energy measurement; Grain boundaries; Nonhomogeneous media; Probes; Silicon; Voltage; Zinc oxide;
fLanguage :
English
Journal_Title :
Components, Hybrids, and Manufacturing Technology, IEEE Transactions on
Publisher :
ieee
ISSN :
0148-6411
Type :
jour
DOI :
10.1109/TCHMT.1985.1136520
Filename :
1136520
Link To Document :
بازگشت