Title :
Experimental and theoretical investigation for temperature characteristics and propagation losses of SAWs on SiO2/Al/LiTaO3
Author :
Asai, Kengo ; Hikita, Mitsutaka ; Isobe, Atsushi ; Sakiyama, Kazuyuki ; Tada, Takeshi
Author_Institution :
Central Res. Lab., Hitachi Ltd., Tokyo, Japan
Abstract :
Improvement of temperature coefficients of frequency (TCFs) for LiTaO3 substrate was investigated. SAW resonators formed on SiO2/Al/36°Y-X LiTaO3 substrate with various kinds of SiO2 relative thickness were examined experimentally and theoretically. A zero TCF at fr was obtained for h/λ≅0.31, while that at fa was obtained for h/λ≅0.36 from experiments. Moreover, the experimental propagation losses revealed also different characteristics between fr and fa with regard to h/λ. These results can not be obtained by the conventional simulation procedures assuming the uniform SiO2 film and uniform Al film on LiTaO3 substrate. We not only applied the coupled finite-element and analytical-solution method to SiO2/Al/36°Y-X LiTaO3 substrate but also assumed same periodic unevenness for the surface of SiO2 as that determined from the Al electrodes. Very good agreements between experimental and the theoretical results were achieved.
Keywords :
aluminium; digital simulation; elemental semiconductors; finite element analysis; lithium compounds; silicon; surface acoustic wave resonators; surface acoustic waves; LiTaO3; LiTaO3 substrate; SAW resonators; SiO2-Al-LiTaO3; SiO2/Al/LiTaO3; coupled finite-element/analytical-solution method; propagation losses; temperature characteristics; temperature coefficients of frequency; Electrodes; Propagation losses; Resonant frequency; Resonator filters; Sawing machines; Shape; Substrates; Surface acoustic wave devices; Surface acoustic waves; Temperature distribution;
Conference_Titel :
Ultrasonics Symposium, 2002. Proceedings. 2002 IEEE
Print_ISBN :
0-7803-7582-3
DOI :
10.1109/ULTSYM.2002.1193391
