Characterization of Leakage Current Mechanisms for Aerosol-deposited BaTiO3 Thin Films at Room Temperature

다국어 초록 (Multilingual Abstract)

BaTiO3 thin films having different thickness of 0.2-2.2 μm were fabricated on flat Cu and stainlesssteel (SUS) substrates by using aerosol deposition (AD) at room temperature. The dependence of the leakage current on the thickness of the BaTiO3 thin films was measured, and the leakage current mechanisms were investigated to clarify the origins of the leakage currents. As a result of the measurements and examination, the leakage currents are highest for the thinnest BaTiO3films, and by decreasing the thickness of the films, the leakage current mechanism was changed from Poole-Frenkel emission to a modified-Schottky (M-S) emission. In particular, in the case of BaTiO3thin films with 0.2 μm-thick which is minimum thickness on SUS substrates, the dominant leakage current mechanism was M-S emission at low electric fields, the Fowler-Nordheim tunneling appeared as the primary leakage current mechanism at high electric fields due to electric-field concentration.
Consequently, the origins of leakage current are suggested to be microscopic defects, such as oxygen vacancies, acting as donors in the BaTiO3 films and the ununiform electric-field concentration at the rough interfaces between the BaTiO3 films and the metal substrates at high electric fields.

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