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Detailed Program
Paper Number : EL-I08
Time Frame : 13:55~14:20
Presentation Date : Friday, 28, November
Session Name : Electronic Ceramics
Session Chair 1# : Eung Soo Kim
Session Chair 2# : Hisao Suzuki
Thermally Stimulated Depolarization Current Analysis for the Dielectric Phenomena of BaTiO3-based Multi Layer Ceramic Capacitor
Seok-Hyun Yoon
Samsung Electro-Mechanics Co. Ltd
Thermally stimulated depolarization current (TSDC) can provide information about defect-related phenomena such as defect dipole, charge trapping/detrapping, and space charge etc.. In this study the dielectric aging and I (Current)-V (Voltage) characteristics of BaTiO3-based multi-layer ceramic capacitors were investigated utilizing TSDC analysis. The increase of Mn concentration significantly increased the aging rate. TSDC of low Mn concentration specimen showed one peak, whereas Mn-increased specimen showed two peaks. The first and second peak is supposed to be caused by the phase transition of the undoped core-region and the defect dipole Mn such as MnTi"-VO•• or MnTi'-VO••, respectively. On the other hand, the increase of Dy concentration in the Dy and Mn-codoped BaTiO3 system significantly decreased the aging rate, and caused a disappearance of the thermally stimulated depolarization current (TSDC) peak associated with the defect dipole of Mn such as MnTi"-VO•• or MnTi'-VO•• which was observed in low Dy-concentration specimen. These results experimentally demonstrate that the dielectric aging is controlled by the defect dipoles, and that the rare earth element, Dy, decreases their concentration, and thereby the dielectric aging is reduced. In the I (Current)-V (Voltage) characteristics of Mn-doped BaTiO3 system, the increase of Mn concentration reduced the slope of current increase with increasing dc field, and enhanced the dc field to the abrupt increase of current and thereby breakdown. A peak of thermally stimulated depolarization current (TSDC) beyond 300C associated with trapped space charges appeared, which increased by the increase of Mn concentration. In addition, the peak intensity increased to a maximum value and then decreased again with increasing polarization dc field in TSDC measurement. Its activation energies were around 1.9 eV for all specimens, which is very close to the energy level for the ionization of Mn3+/Mn2+. These results experimentally demonstrate the role of the variable valence acceptor Mn as trapping center for injected charges, and the occurrence of field enhanced trap charge release, and therefore, the conduction mechanism can be described by the SCL model incorporating the Poole-Frenkel effect.

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