Fabrication of KNbO_3 Thin Film and Application to SAW Device for Future Mobile Tohoku University Communication

KNbO_3薄膜的制备及其在未来移动东北大学通信SAW器件中的应用

• 批准号: 11555089
• 负责人: ODAGAWA Hiroyuki
• 金额: $ 8.83万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11555089/
• 关键词: KNbO_3; Surface Acoustic Wave; SAW Filter; Piezoelectric Thin Film; ニオブ酸カリウム

In this research, properties of KNbO_3 films, which was deposited on SrTiO_3 (STO) substrate using a 2 cathode sputtering method and a metal organic chemical vapor deposition (MOCVD) method, were investigated for surface acoustic wave (SAW) applications.1. We investigated the theoretical properties of SAW in KNbO_3 thin film on STO and Si substrates. As the results, we found that (001)<100>KNbO_3// (110)<1-10>STO was the best combination between the substrate and the orientation of the KNbO_3 thin film in the view of both SAW properties and a lattice matching. In this case, electromechanical coupling coefficient (k^2) is 10.4% for the film thickness of 1 wavelength.2. We investigated a best combination of the targets composition of the sputtering. Experimentally, we found that K_2CO_3 : Nb_2O_5=1 : 0 and K_2CO_3 : Nb_2O_5=3 : 1 was the best one, and we could successfully obtained (001) oriented KNbO_3 thin film on STO substrates.3. We observed the polarization distribution of the KNbO_3 thin films using scanning nonlinear dielectric microscope (SNDM), which was developed by one of the investigators of our research project. The results showed that the as-grown KNbO_3 film had an uniform polarization and its direction was along the surface normal if the film was fabricated by appropriate conditions. Also, as the result of the comparison between the polarization measurements and experimentally measured SAW properties, we could observe a large correlation between them. It means that we can estimate the SAW properties of thin films by SNDM without fabricate an actual SAW device

本研究采用双阴极溅射法和金属有机物化学气相沉积（MOCVD）法在SrTiO_3（STO）衬底上制备了KNbO_3薄膜，并对其声表面波特性进行了研究.本文研究了STO和Si衬底上KNbO_3薄膜的声表面波理论特性。结果表明：（001）<100>KNbO_3//（110）<1-10>STO是KNbO_3薄膜的最佳基片和取向组合。在这种情况下，机电耦合系数（k^2）对于1波长的膜厚度为10.4%。研究了溅射靶成分的最佳组合。实验发现，K_2CO_3：Nb_2O_5=1：0和K_2CO_3：Nb_2O_5=3：1是最佳的制备条件，可以在STO衬底上成功制备出（001）取向的KNbO_3薄膜.利用本课题组研制的扫描非线性介电显微镜（SNDM）对KNbO_3薄膜的极化分布进行了观察。结果表明，在适当的工艺条件下，KNbO_3薄膜具有均匀的极化方向，极化方向沿着表面法线。此外，作为极化测量和实验测量的SAW特性之间的比较的结果，我们可以观察到它们之间的大的相关性。这意味着我们可以在不制作实际声表面波器件的情况下，用SNDM方法来估计薄膜的声表面波特性

项目成果

Hiroyuki Odagawa: "SAW Device beyond 5 GHz"International Journal of High Speed Electronics and Systems. (in press). (2001)

Hiroyuki Odakawa：“超过 5 GHz 的 SAW 器件”国际高速电子与系统杂志。

Hiroyuki Odagawa: "Simultaneous observation of nano-sized ferroelectric domains and surface morphology using scanning nonlinear dielectric microscopy"Surface Science. 463. L621-L625 (2000)

小田川博之：“使用扫描非线性介电显微镜同时观察纳米级铁电域和表面形态”表面科学。

Clemens C W Ruppel: "Advances in Surface Acoustic Wave Technology, Systems and Applications (Volume 2)"World Scientific Publishing Pte Ltd. (2001)

Clemens C W Ruppel：“表面声波技术、系统和应用的进展（第 2 卷）”World Scientific Publishing Pte Ltd. (2001)

Hiroyuki Odagawa: "Observation of Nano-Size Ferroelectric Domains and Crystal Polarity Using Scanning Nonlinear Dielectric Microscopy"Ferroelectrics. (in press). (2001)

小田川博之：“使用扫描非线性介电显微镜观察纳米尺寸铁电畴和晶体极性”铁电体。

Yasuo Cho: "Quantitative study on the nonlinear piezoelectric effect in KNbO_3 single crystals for a super highly efficient SAW elastic convolver"Journal of Applied Physics. 87. 3457-3461 (2000)

Yasuo Cho：“用于超高效SAW弹性卷积器的KNbO_3单晶非线性压电效应的定量研究”应用物理杂志。