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Meso-scale Nondestructive Observation System of Self-organized Dislocation Network using Scanning Electron Acoustic Microscopy

扫描电声显微镜自组织位错网络细观无损观测系统

基本信息

批准号：
12555028
负责人：
SHIBUTANI Yoji
金额：
$ 5.57万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

In order to investigate internal structures generated by self-organized dislocation network in various kinds of materials and loading states, we have developed a nondestructive observation system using acoustic wave by the electron beam. In this system, heat wave is firstly generated on the surface of the specimen by the irradiation of blanking and focused electron beam of the Scanning Electron Microscope (SEM). Then the heat wave is transferred into sound wave, and it propagates within the specimen as elastic wave. Difference of the local thermal property of the material is converted into an electric signal by a piezoelectric transducer (PZT) attached onto the back side of the specimen. This system is called the scanning electron acoustic microscopy (SEAM). It makes us enable to observe both the surface of the specimen by SEM mode and the nondestructive inside structure by SEAM. A commercial amplifier is not enough to detect the electric signals by the PZT, because these signals are very feeble and high frequency. We developed a newly head amplifier using transistors. This head amplifier transforms an impedance and amplifies the electric signals. And we used an instrumentation amplifier to eliminate the noises from detected signals. Then the detected signals are amplified by a lock-in amplifier synchronized to the blanking frequency of an electron beam. The performance of this developed head amplifier seems to be excellent and it makes us enable to detect the electron acoustic signals sufficiently.We obtained ultrasonic signal by the SEAM using the Diamond Like Carbon (DLC) thin film laminated on single crystalline silicon wafer. And we developed a portrayal system that draws these signals as two dimensional phase-contrast images on the display.

为了研究各种材料和加载状态下自组织位错网络产生的内部结构，我们开发了一种电子束声波无损观察系统。在该系统中，首先通过扫描电子显微镜（SEM）的消隐和聚焦电子束的照射在样品表面产生热波。然后，热波转换成声波，并作为弹性波在试样中传播。材料的局部热性能的差异被转换成一个电信号的压电传感器（PZT）连接到背面的试样。这种系统被称为扫描电子声学显微镜（SEAM）。它使我们既能用SEM模式观察试样的表面，又能用SEAM模式无损地观察试样的内部结构。由于压电陶瓷产生的电信号非常微弱且频率很高，普通的放大器不足以检测到这些电信号。我们研制了一种新型晶体管前置放大器。该前置放大器转换阻抗并放大电信号。并利用仪表放大器消除了检测信号中的噪声。然后，检测到的信号由与电子束的消隐频率同步的锁定放大器放大。我们利用类金刚石（DLC）薄膜在单晶硅上的叠层结构，通过SEAM获得了超声信号。我们开发了一个描绘系统，它将这些信号绘制成显示器上的二维相位对比图像。