摘要
Ferroelectric Bi3.25La0.75Ti3O12 (BLT) and Bi3.15Nd0.85Ti3O12 (BNT) thin films were fab- ricated on Pt/TiO2/SiO2/Si (100) substrates by a modified sol-gel technique. X-ray diffraction indicated that these films were of single phase with random polycrystal- line orientations. The surface morphologies of the films were observed by scanning electron microscope, showing uniform, dense films with grain size of 50―100 nm. Well-saturated hysteresis loops of the films were obtained in metal-ferroelectric- metal type capacitors with Cu top electrodes at an applied voltage of 400 kV/cm, giving the remanent polarization (2Pr) and coercive field (2Ec) values of the films of 25.1 μC/cm2 and 203 kV/cm for BLT, and 44.2 μC/cm2 and 296 kV/cm for BNT, re- spectively. Moreover, these capacitors did not show fatigue behaviors after up to 1.75×1010 switching cycles at the test frequency of 1 MHz, suggesting a fatigue-free character. The influences of the La3+ and Nd3+ doping on the properties of the films were comparatively discussed.
Ferroelectric Bi3.25La0.75Ti3O12 (BLT) and Bi3.15Nd0.85Ti3O12 (BNT) thin films were fab- ricated on Pt/TiO2/SiO2/Si (100) substrates by a modified sol-gel technique. X-ray diffraction indicated that these films were of single phase with random polycrystal- line orientations. The surface morphologies of the films were observed by scanning electron microscope, showing uniform, dense films with grain size of 50―100 nm. Well-saturated hysteresis loops of the films were obtained in metal-ferroelectric- metal type capacitors with Cu top electrodes at an applied voltage of 400 kV/cm, giving the remanent polarization (2Pr) and coercive field (2Ec) values of the films of 25.1 μC/cm2 and 203 kV/cm for BLT, and 44.2 μC/cm2 and 296 kV/cm for BNT, re- spectively. Moreover, these capacitors did not show fatigue behaviors after up to 1.75×1010 switching cycles at the test frequency of 1 MHz, suggesting a fatigue-free character. The influences of the La3+ and Nd3+ doping on the properties of the films were comparatively discussed.
作者
LI MeiYa1,2, PEI Ling1, LIU Jun1, YU BenFang1, GUO DongYun1, SUN XiaoHua3 & ZHAO XingZhong1,2 1 Department of Electronic Science and Technology, School of Physical Science and Technology, Wuhan University, Wuhan 430072, China
2 Key Laboratory of Acoustic and Photonic Material and Device of the Ministry of Education, Wuhan Uni- versity, Wuhan 430072, China
3 School of Mechanical and Material Engineering, China Three Gorges University, Yichang 443002, China
基金
the National Key Basic Research and Development Program of China (Grant No. 2006CB932305)
the Natural Science Foundation of Hubei Province, China (Grant No. 2004ABA082)
