The influence of surface roughness on the electric conduction process in amorphous Ta{sub 2}O{sub 5} thin films
Amorphous Ta{sub 2}O{sub 5} thin films were deposited by radio-frequency magnetron sputtering at the substrate temperatures of 100, 200, and 300 C, respectively. The electrical properties of Ta{sub 2}O{sub 5} thin films were investigated as a function of substrate temperature and film thickness. The leakage current of the Ta{sub 2}O{sub 5} films was in the order of 10{sup {minus}5} to 10{sup {minus}6} A/cm{sup 2} for an applied field of 1 MV/cm. The charge storage capacitances ({epsilon}E{sub breakdown}) were 7.7 (100 C), 7.9 (200 C), and 3.7 (300 C) {micro}C/cm{sup 2}. Most of the electrical analyses were performed with the data obtained for the Ta{sub 2}O{sub 5} thin films deposited at 200 C substrate temperature because they showed optimum electrical properties. The dominant conduction mechanism changed from Schottky emission current at low field to Poole-Frankel current at the high field. With increasing film thickness, the surface roughness increased, whereas the transition fields from the electrode-limited current to the bulk-limited current process decreased. To verify the effect of this surface roughness on the electrical conduction mechanism, a two-dimensional numerical simulator, MEDICI, was used to simulate the electric field distribution at the bulk region of the thin film and the interface region between the thin film and electrode.
- Research Organization:
- Korea Univ., Seoul (KR)
- OSTI ID:
- 20003179
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 9 Vol. 146; ISSN JESOAN
- Country of Publication:
- United States
- Language:
- English
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