2005 Fiscal Year Final Research Report Summary
PREPARATION OF PIEZOELECTRIC PZT THICK FILMS BY TEMPLATED GRAIN GROWTH
| Project/Area Number |
16560624
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
WANG Zhan Jie Tohoku University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (20323074)
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| Co-Investigator(Kenkyū-buntansha) |
KOKAWA Hiroyuki Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (10133050)
SATO Yutaka Tohoku University, Graduate School of Engineering, Research Associate, 大学院・工学研究科, 助手 (00292243)
MAEDA Ryutaro National Institute of Advanced Science and Technology, Senior Researcher, 主任研究員 (60357986)
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| Project Period (FY) |
2004 – 2005
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| Keywords | PZT thin films / sol-gel method / pulsed-laser deposition (PLD) / template grain growth / preferred orientation / electrical propeties / piezoelectric propeties / micro actuator |
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| Research Abstract |
Pb(Zr_xTi_<1-x>)O_3 (PZT) thin films were in situ-grown on Pt/Ti/SiO_2/Si substrates by a hybrid process consisting of the sol-gel method and pulsed-laser deposition (PLD). The deposition temperature to obtain the perovskite phase in the hybrid process is 460℃, and is significantly lower than that in the case of direct film deposition by PLD on a Pt/Ti/SiO_2/Si substrate. X-ray diffraction analysis indicated that the preferred orientation of PZT films can be controlled using the template layer deposited by the sol-gel method and highly (111)- or (100)-oriented PZT films were obtained. A transmission electron microscopy (TEM) image showed that the film had a polycrystalline columnar microstructure extending through its thickness, and no sharp boundary was observed between the layers deposited by the sol-gel method and PLD. A high-resolution electron microscopy image and electron diffraction analysis revealed that the crystalline lattice of the layers deposited by the sol-gel method and
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PLD was continuous and there was no difference in crystalline orientation between the layers. These results indicate that the solid-phase epitaxial effect between the PZT layers deposited by the sol-gel method and PLD decreases the deposition temperature to obtain the perovskite phase during PLD, and causes the films to exhibit the same preferred orientation as that of the layer deposited by the sol-gel method. The effects of substrate temperature on the crystalline phase, microstructure and electrical properties of the hybrid PZT films were also investigated. It is clear that the PZT films deposited by PLD at a substrate temperature of 420℃ by the hybrid process are amorphous. The deposition by the hybrid process at a substrate temperature of 460℃ can produce perovskite PZT films. With increasing substrate temperature, the microstructure of the hybrid films becomes uniform and their electrical properties increase. The PZT films in situ-deposited at 550℃ showed a uniform microstructure and exhibited good electrical properties. The dielectric constants and remanent polarization of the PZT films were approximately 1200 and 27.3μC/cm^2, respectively. The template grain growth in the hybrid process is effective for obtaining PZT films with good properties at a low deposition temperature. Less
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