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URN etd-0906105-121203 Statistics This thesis had been viewed 3005 times. Download 1019 times. Author Hong-yi Su Author's Email Address No Public. Department Electro-Optical Engineering Year 2004 Semester 2 Degree Master Type of Document Master's Thesis Language English Page Count 82 Title Fabrication of high frequency ZnO
thin film SAW devices with different buffer layers by RF magnetron sputtering
Keyword ZnO sapphire Al2O3 Al2O3 sapphire ZnO Abstract Among recently developed piezoelectric thin film materials, ZnO has been considered to be very promising for fabricating thin film surface acoustic wave (SAW) devices. ZnO thin films have been deposited on quartz, Si, GaAs, InP, sapphire (Al2O3), and diamond substrates. In these substrates materials, sapphire is widely used for high frequency SAW device due its high acoustic velocity. However, the sapphire substrate is more expensive than Si wafer, and it is still very difficult to grow large size of Al2O3 single crystal. In this study, the Al2O3 buffer layer was served as a lower-price alternative to the expensive sapphire substrates. We adopt the ZnO thin film on SiO2/Si substrate with Al2O3 buffer layer as a promising substrate for high-frequency SAW device.
In this work, we have been successfully developed the ZnO on Al2O3 buffer by RF magnetron sputtering. Interdigital transducers (IDTs) were fabricated on ZnO thin film surface by a conventional photolithographic technique. The center frequency of SAW device with Al2O3 (4.8μm) buffer was measured to be about 408 MHz, which was much higher than that (265 MHz) of ZnO/SiO2/Si SAW device. The center frequency of ZnO/Al2O3/SiO2/Si SAW device is approach to that of the ZnO/sapphire SAW device. It is beneficial to replace sapphire substrate for high frequency SAW device. And we believe that the SAW devices based on Al2O3 buffer will be applied on high frequency devices in the future.
Advisor Committee Wen-ching shih - advisor
Mu-shing Wu - co-chair
none - co-chair
Files Date of Defense 2005-07-28 Date of Submission 2005-09-06