Title :
Temperature effect on the characteristics of surface acoustic wave on SiO2 thin films
Author :
Cheng, Chien-Chuan ; Chung-Jen Chang ; Chen, Ying-Chung ; Kao, Kuo-Sheng
Author_Institution :
Dept. of Electron. Eng., De Lin Inst. of Technol., Taipei, Taiwan
Abstract :
The surface acoustic wave (SAW) propagation characteristics of a layered structure consisting of a SiO2 thin film on z-cut LiNbO3 substrate in company with temperature dependence of frequency of this structure has been studied experimentally. The temperature coefficient of frequency (TCF) of SAW devices was obtained by a network analyzer. A SAW device on the lithium niobate (LiNbO3) exhibits a large negative TCF. It revealed that the SiO2 thin film was introduced as compensation layer for improving the temperature stability. The TCF of the SiO2/LiNbO3 based structure was significantly decreased due to the SiO2 thin film deposition. The TCF of SAW on the SiO2/LiNbO3 device was measured to be about -51 ppm/°C at h/λ=0.12, where h was the thickness of SiO2 film and λ was the wavelength of SAW. It indicated that the SiO2 thin film deposited on LiNbO3 substrate could improve the temperature stability, as compared with the TCF of SAW on bare LiNbO3. Furthermore, the phase velocity (Vp) of SAW on SiO2/LiNbO3 substrate was not altered by the increase of SiO2 thickness (h/λ).
Keywords :
acoustic wave propagation; compensation; lithium compounds; silicon compounds; surface acoustic wave devices; thermal stability; thin film devices; LiNbO3; SAW devices; SAW propagation; SiO2; SiO2 thin films; compensation layer; layered structure; surface acoustic wave propagation; temperature coefficient of frequency; temperature stability; z-cut LiNbO3 substrate; Acoustic propagation; Acoustic waves; Frequency; Sputtering; Stability; Substrates; Surface acoustic wave devices; Surface acoustic waves; Temperature; Transistors;
Conference_Titel :
Ultrasonics Symposium, 2004 IEEE
Print_ISBN :
0-7803-8412-1
DOI :
10.1109/ULTSYM.2004.1418198
