公开(公告)号：WO1997049182A1

公开(公告)日：1997-12-24

申请号：PCT/JP1997000872

申请日：1997-03-18

Applicant: TDK CORPORATION

Inventor： TDK CORPORATION ,  INOUE, Kenji ,  SATO, Katsuo

IPC: H03H09/145

CPC classification number: H03H9/02834 ,  H03H9/0259

Abstract: A surface acoustic wave device having interdigital type electrodes on the surface of a substrate composed of a single crystal of langasite belonging to a point group (32). The substrate is given a small absolute value of SAW speed temperature coefficient TCV, a large electromechanical coupling coefficient k , and a slow SAW speed by optimizing the combination of the cutting angle of the substrate from the single crystal and the surface acoustic wave propagating direction. Therefore, the temperature stability of the device can be improved and the passing bandwidth of the device as a filter can be widened. In addition, the size of the device can be reduced and, especially, excellent characteristics as the surface acoustic wave film for intermediate frequencies of mobile communication terminal equipment can be obtained.

Abstract translation: 一种表面声波装置，其在由属于点组（32）的由单晶的单晶构成的基板的表面上具有叉指型电极。 通过优化基板从单晶的切割角与表面声波的组合，给出基板具有小的SAW速度温度系数的绝对值TCV，大的机电耦合系数k <2和慢的SAW速度 传播方向。 因此，能够提高装置的温度稳定性，能够扩大作为过滤器的装置的通过带宽。 此外，可以减少装置的尺寸，特别是可以获得用于移动通信终端设备的中频的表面声波膜的优异特性。

公开(公告)号：EP0869609B8

公开(公告)日：2004-01-02

申请号：EP97944141.7

申请日：1997-10-16

Applicant: TDK Corporation

Inventor： INOUE, Kenji ,  SATO, Katsuo

IPC: H03H9/145 ,  H03H9/25

CPC classification number: H03H9/0259 ,  H03H9/02574

Abstract: The size of a surface acoustic wave device having interdigital electrodes on the surface of a substrate is reduced and the selectivity of the device is improved, and then, the band of the device is widened. For this purpose, a single crystal of langasite belonging to a point group (32) is used for the substrate. In addition, a piezoelectric film is formed to cover the surface of the substrate and interdigital electrodes, or a film is provided on the surface of the substrate and the interdigital electrodes are formed on the surface of the film. Alternatively, the piezoelectric film is provided on the surfaces of the substrate and electrodes and a counter electrode film is formed on the surface of the film, or the counter electrode film is provided on the surface of the substrate and the piezoelectric film is formed on the counter electrode film and the interdigital electrodes are formed on the surface of the piezoelectric film. The piezoelectric film is formed of zinc oxide having a piezoelectric axis oriented nearly perpendicularly to the surface of the substrate. The cutting angle of the substrate from the single crystal of langasite, the surface acoustic wave propagating direction of the substrate, and the thickness of the piezoelectric film are optimized in accordance with the structure of the piezoelectric film.

Abstract translation: 在基片表面上具有叉指型电极的表面声波器件的尺寸减小，并且器件的选择性提高，然后器件的带宽变宽。 为此目的，属于点群（32）的硅酸镧单晶被用于基底。 此外，形成压电膜以覆盖基板和叉指电极的表面，或者在基板的表面上提供膜，并且在膜的表面上形成叉指电极。 或者，将压电膜设置在基板和电极的表面上，并且在膜的表面上形成对电极膜，或者将对电极膜设置在基板的表面上，并且将压电膜形成在 对电极膜和叉指电极形成在压电膜的表面上。 压电膜由具有与基板的表面大致垂直的压电轴的氧化锌形成。 根据压电薄膜的结构，优化了从硅酸镓镧单晶，衬底的表面声波传播方向以及压电薄膜厚度的衬底切割角度。

公开(公告)号：EP0869609B1

公开(公告)日：2003-08-06

申请号：EP97944141.7

申请日：1997-10-16

Applicant: TDK Corporation

Inventor： INOUE, Kenji ,  SATO, Katsuo

IPC: H03H9/145 ,  H03H9/25

CPC classification number: H03H9/0259 ,  H03H9/02574

公开(公告)号：EP0869609A1

公开(公告)日：1998-10-07

申请号：EP97944141.7

申请日：1997-10-16

Applicant: TDK Corporation

Inventor： INOUE, Kenji ,  SATO, Katsuo

IPC: H03H9/145 ,  H03H9/25

CPC classification number: H03H9/0259 ,  H03H9/02574

Abstract: An object of the invention is to provide a surface acoustic wave device comprising a substrate and an interdigital electrode on the surface thereof, which is reduced in size and improved in selectivity, and has a broad band. To achieve this object, a langasite single crystal belonging to a point group 32 is first used for the substrate. Secondly, I. a piezoelectric film is provided for covering the surface of the substrate and the surface of the interdigital electrode, II. a piezoelectric film is provided on the surface of the substrate and the interdigital electrode is provided on the surface of the piezoelectric film, III. a piezoelectric film is provided for covering the surface of the substrate and the surface of the interdigital electrode and an opposite electrode film is provided on the surface of the piezoelectric film, or IV. an opposite electrode film is provided on the surface of the substrate, a piezoelectric film is provided on the opposite electrode film and the interdigital electrode is provided on the surface of the piezoelectric film. The piezoelectric film is made up of zinc oxide, and has a piezoelectric axis oriented substantially perpendicularly with respect to the surface of the substrate. The cut angle of the substrate cut out of the langasite single crystal, the propagation direction of surface acoustic waves on the substrate, and the thickness of the piezoelectric film are optimized depending on how to provide the piezoelectric film.

Abstract translation: 本发明的目的是提供一种弹性表面波器件，其表面上具有基板和交叉指状电极，尺寸减小，选择性提高，具有宽带。 为了达到这个目的，首先使用属于点组32的偏光石单晶作为基板。 其次，提供一种用于覆盖基板的表面和叉指电极表面的压电膜，II。 在基板的表面上设置压电膜，并且在压电膜的表面上设置叉指电极，III。 提供了用于覆盖基板的表面和叉指电极的表面的压电膜，并且在压电膜的表面上设置了相对的电极膜，或IV。 在基板的表面上设置相对的电极膜，在相对电极膜上设置压电膜，在压电膜的表面上设置叉指电极。 压电膜由氧化锌构成，并具有相对于基板的表面基本垂直取向的压电轴。 根据如何提供压电膜，优化从硅酸盐单晶切割的基板的切割角度，基板上的表面声波的传播方向和压电膜的厚度。