The Study of Fabrication Surface Acoustic Wave Devices on AlN Films
| Autor: | 黃翊峰 |
|---|---|
| Rok vydání: | 1999 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 87 The deposition of AlN film on non-piezoelectric substrates were demonstrated to fabricate the SAW devices. The advantage is that the process is compatible with semiconductor technology. The surface acoustic wave (SAW) devices play an important role for communication system and signal processing. AlN films posses excellent piezoelectricity, high surface acoustic wave velocity, substantial electromechanical coupling coefficient, and good temperature stability. The acoustic velocity along the c-axis of AlN is fastest; to generate only shear waves, the c-axis of AlN films must be parallel to the substrate surface. Therefore to control the preferred orientation of AlN films with c-axis parallel to substrate is important for the application of SAW devices. In this study,the AlN films with c-axis parallel to substrates with good adhesion and strong piezoelectricity were deposited on several substrates by reactive RF magnetron sputtering in off-axis configuration, which is to prevent the high energy particle bombardment.. The dependence of crystallization and surface morphology on growth conditions were investigated. The interdigital transducers (IDTs) were fabricated on the films to estimate the surface acoustic wave properties using AlN thin films. The XRD results showed that the structural characteristics and surface morphology were found to be sensitive to the deposition parameters. The optimized condition to deposit AlN films with c-axis parallel to the substrate surface are substrate temperature 350℃, R.F. 150W, N2 content 75% and total pressure 80 mTorr. Besides, Single finger interdigital transducers with wavelength 34.88mm were fabricated on the AlN thin films. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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