A study on properties of SAW and the magnetic thin-film bond

We manufactured photo mask to make surface acoustic wave (SAW) filter that use special quality of these LiNbO₃ piezoelectric material (100). To make IDT electrode, we evaporated aluminum about 6000 Å, and achieved lithography process by using e-beam evaporator. Filament evaporation method was selected to evaporate nickel magnetic thin film between Tx-IDT terminal and Rx-IDT terminal. Thickness of evaporated nickel was about 4000 Å. Width of IDT electrode that is used here are 50 μm and space between IDT electrodes is 50 μm. Metal piece is 8 pair, the length of metal piece is 8 mm and the whole size is 52 mm×24 mm. The calculated SAW is 200 μm. It is confirmed that manufactured LiNbO₃-IDT´s center frequency is 18.1 MHz. The average velocity of SAW, that propagates LiNbO₃-IDT´s Tx-IDT and Rx-IDT both terminal, measured v=3888±2.565m/s. And SAW´s average velocity, that propagates LiNbO₃-Ni-IDT´s Tx-IDT and Rx-IDT both terminal, measured ^v=3827±1.474m/s. While SAW passing magnetic thin films, its velocity decreased about 1.5% (61m/s).