TY - JOUR
T1 - Contrasting conduction mechanisms of two internal barrier layer capacitors
T2 - (Mn, Nb)-doped SrTiO3 and CaCu3Ti4O12
AU - Tsuji, Kosuke
AU - Chen, Wei Ting
AU - Guo, Hanzheng
AU - Lee, Wen Hsi
AU - Guillemet-Fritsch, Sophie
AU - Randall, Clive A.
N1 - Funding Information:
This work was supported by the National Science Foundation, as part of the Center for Dielectrics and Piezoelectrics under Grant No. IIP-1361571 and 1361503. Authors are grateful to Materials Characterization Lab staff at The Pennsylvania State University for their helpful discussions. K. Tsuji would like to thank the ITO Foundation for International Education Exchange for financial support. W. T. Chen would like to thank MOST 104-2622-E-006-038-CC3 Ministry of Science and Technology R.O.C. for the financial support. Thanks to Dr. Bertrand Barbier for supplying some of the CCTO samples.
Publisher Copyright:
© 2017 Author(s).
PY - 2017/2/14
Y1 - 2017/2/14
N2 - The d.c. conduction is investigated in the two different types of internal barrier layer capacitors, namely, (Mn, Nb)-doped SrTiO3 (STO) and CaCu3Ti4O12 (CCTO). Scanning electron microscopy (SEM) and Capacitance - Voltage (C-V) analysis are performed to estimate the effective electric field at a grain boundary, EGB. Then, the d.c. conduction mechanism is discussed based on the J (Current density)-EGB characteristics. Three different conduction mechanisms are successively observed with the increase of EGB in both systems. In (Mn, Nb)-doped STO, non-linear J-EGB characteristics is temperature dependent at the intermediate EGB and becomes relatively insensitive to the temperature at the higher EGB. The J- EGB at each regime is explained by the Schottky emission (SE) followed by Fowler-Nordheim (F-N) tunneling. Based on the F-N tunneling, the breakdown voltage is then scaled by the function of the depletion layer thickness and Schottky barrier height at the average grain boundary. The proposed function shows a clear linear relationship with the breakdown. On the other hand, F-N tunneling was not observed in CCTO in our measurement. Ohmic, Poole-Frenkel (P-F), and SE are successively observed in CCTO. The transition point from P-F and SE depends on EGB and temperature. A charge-based deep level transient spectroscopy study reveals that 3 types of trap states exist in CCTO. The trap one with Et ∼ 0.65 eV below the conduction band is found to be responsible for the P-F conduction.
AB - The d.c. conduction is investigated in the two different types of internal barrier layer capacitors, namely, (Mn, Nb)-doped SrTiO3 (STO) and CaCu3Ti4O12 (CCTO). Scanning electron microscopy (SEM) and Capacitance - Voltage (C-V) analysis are performed to estimate the effective electric field at a grain boundary, EGB. Then, the d.c. conduction mechanism is discussed based on the J (Current density)-EGB characteristics. Three different conduction mechanisms are successively observed with the increase of EGB in both systems. In (Mn, Nb)-doped STO, non-linear J-EGB characteristics is temperature dependent at the intermediate EGB and becomes relatively insensitive to the temperature at the higher EGB. The J- EGB at each regime is explained by the Schottky emission (SE) followed by Fowler-Nordheim (F-N) tunneling. Based on the F-N tunneling, the breakdown voltage is then scaled by the function of the depletion layer thickness and Schottky barrier height at the average grain boundary. The proposed function shows a clear linear relationship with the breakdown. On the other hand, F-N tunneling was not observed in CCTO in our measurement. Ohmic, Poole-Frenkel (P-F), and SE are successively observed in CCTO. The transition point from P-F and SE depends on EGB and temperature. A charge-based deep level transient spectroscopy study reveals that 3 types of trap states exist in CCTO. The trap one with Et ∼ 0.65 eV below the conduction band is found to be responsible for the P-F conduction.
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U2 - 10.1063/1.4976011
DO - 10.1063/1.4976011
M3 - Article
AN - SCOPUS:85013215116
VL - 121
JO - Journal of Applied Physics
JF - Journal of Applied Physics
SN - 0021-8979
IS - 6
M1 - 064107
ER -