| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO Yasushi Graduate School of Engineering, Tohoku University, Associate Professor, 大学院・工学研究科, 助教授 (20312598)
SUEMITSU Maki Research Institute of Electrical Communications, Tohoku University, Associate Professor, 電気通信研究所, 助教授 (00134057)
NIWANO Michio Research Institute of Electrical Communications, Tohoku University, Professor, 電気通信研究所, 教授 (20134075)
ONO Yuu Graduate School of Engineering, Tohoku University, Research Associate, 大学院・工学研究科, 助手 (70271880)
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| Research Abstract |
Ultrasonic microspectroscopy technology, using the line-focus-beam (LFB) and plane-wave ultrasonic material characterization system, has been applied to resolve material problems concerned with single crystal substrate (LiNbOィイD23ィエD2, LiTaOィイD23ィエD2, Si, GaAs) for electronic devices and with proton-exchanged, implanted layers, epitaxial or amorphous films on the substrates used in the device fabrication processes.
1. The reliable LFB system with high accuracy in leaky surface-acoustic-wave (LSAW) velocity measured on the water-loaded specimen surface has been established for accurate and efficient characterization of material properties, by developing a temperature-controlled pure water supply system and a sample transfer system. For the system calibration, the standard specimens of GGG, Si, Ge, LiNbOィイD23ィエD2, and LiTaOィイD23ィエD2 has been developed.
2. A method of super-precision measurements of lattice parameters by the X-ray diffractometer using the Bond method has been developed, resulting in a very high accuracy of Δd/d<10ィイD1-6ィエD1 for a wide Bragg angle range.
3. To eliminate a serious problem of the back reflection effect, occurring for thin specimens such as wafer substrates, a moving average method to obtain a true velocity from apparent LSAW velocities measured as a function of frequency and an approximated correction method useful for a number of measurement points have been developed.
4. A method of evaluating single crystals such as LiNbOィイD23ィエD2, LiTaOィイD23ィエD2, and GaAs by the LFB system has been established.
5. A method of evaluating and selecting LiNbOィイD23ィエD2 and LiTaOィイD23ィエD2 substrates for SAW devices by the LFB system has been established.
6. A method of analyzing and evaluating proton-exchanged layers on Z-cut LiTaOィイD23ィエD2 crystal substrates and ion-implanted layers on Si crystal substrates has been developed and demonstrated.
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