標題: Ultrathin Oriented BiFeO3 Films from Deposition of Atomic Layers with Greatly Improved Leakage and Ferroelectric Properties
作者: Liu, Yen-Ting
Ku, Ching-Shun
Chiu, Shang-Jui
Lee, Hsin-Yi
Chen, San-Yuan
材料科學與工程學系
加速器光源科技與應用學位學程
Department of Materials Science and Engineering
Master and Ph.D. Program for Science and Technology of Accelrrator Light Source
關鍵字: BiFeO3;atomic layer deposition
公開日期: 8-Jan-2014
摘要: Highly (001)-oriented BiFeO3 ultrathin films of total thickness of less than 10 nm were deposited on Si(001) substrates via deposition of atomic layers (ALD) with a LaNiO3 buffer. A radio-frequency (RF)-sputtered sample of the same thickness was prepared for comparison. The ALD combined with interrupted flow and an exchange reaction between Bi and Fe precursors provides a superior method to grow ternary compounds. According to X-ray diffraction, upon deposition at a temperature of less than 550 degrees C, the only phase in the film was BiFeO3. Anomalous fine structure from synchrotron X-ray diffraction certified the valence bonding through the BiFeO3 (001) diffraction signal. The stoichiometric ratio of BiFeO3 obtained from X-ray photoelectron spectroscopy indicated that ALD has a proportion much improved over the RF preparation, and this is also in agreement with the results for diffraction anomalous fine structure. The use of high-resolution transmission electron and atomic force microscopes showed that the layer structure and morphology from ALD presented a satisfactory coverage, more conformal than that with the RF method. The BiFeO3 thin film deposited with ALD shows excellent leakage, improved at least 1000 times with respect to the RF preparation, making this method suitable for the fabrication of ferroelectric random-access memory devices. From the hysteresis loop, the largest remanent polarization was observed as 2P(r) = 2.0 mu C cm(-2).
URI: http://dx.doi.org/10.1021/am404498y
http://hdl.handle.net/11536/23604
ISSN: 1944-8244
DOI: 10.1021/am404498y
期刊: ACS APPLIED MATERIALS & INTERFACES
Volume: 6
Issue: 1
起始頁: 443
結束頁: 449
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