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標題: Improvement of dielectric properties of Ba0.6Sr0.4TiO3 thin films by MgO doping
作者: Chiu, M.C.
Yao, H.C.
Huang, C.J.
Shieu, F.S.
關鍵字: barium strontium-titanate;tunable microwave applications;electrical-properties;device applications;microstructure;ceramics;(ba;capacitors;memories
Project: Journal of Applied Physics
期刊/報告no:: Journal of Applied Physics, Volume 102, Issue 1.
MgO-doped Ba0.6Sr0.4TiO3 (BST) thin films were synthesized by rf magnetron sputtering at substrate temperature of 750 degrees C using single-phase targets with different MgO contents ranging from 0 to 5 mol %. Microstructure, dielectric constant, and leakage current density of the MgO-doped BST films were characterized to understand the influence of the MgO dopant on film properties. Polycrystalline and perovskite phase solid solution films with a dense microstructure were obtained in all deposition conditions. The thickness of the 0,2, and 5 mol % MgO-doped BST films was measured to be 190, 140, and 150 nm, respectively. The electrical and dielectric properties of the BST-containing capacitors are both found to be improved significantly by doping MgO in the BST films. The voltage-dependent capacitance C-V increases with increasing MgO doping up to 5 mol %. The evidence for the asymmetric distribution of charge carriers in the MgO-BST film is derived from the interfacial layer. The leakage current density of the 5 mol % MgO-doped BST capacitors is nearly two orders of magnitude lower and the dielectric constant is about 45% times higher than that of the undoped BST capacitors. Correlation of the material properties with dielectric properties suggests that the 5 mol % MgO-doped BST films are the optimal choice for applications. (c) 2007 American Institute of Physics.
ISSN: 0021-8979
DOI: 10.1063/1.2748424
Appears in Collections:工學院

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