Title :
The surface acoustic wave propagation characteristics of 64° Y-X LiNbO3 and 36° Y-X LiTaO3 substrates with thin-film SiO2
Author :
Hickemell, F.S. ; Knuth, H.D. ; Dablemont, R.C. ; Hickernell, F.S.
Author_Institution :
Gov. & Space Technol. Group, Motorola Inc., Scottsdale, AZ, USA
Abstract :
The SAW characteristics of thin-film sputtered silicon dioxide (SiO2) on substrates of 64° Y-X lithium niobate (LiNbO 3) and 36° Y-X lithium tantalate (LiTaO3) have been measured in the frequency range from 30 MHz to above 1.0 GHz. Silicon dioxide films in the 500 nm to 2000 nm thickness range were deposited by RF diode sputtering. The SAW velocity, propagation loss, capacitance ratio (Cm/C0), and temperature coefficient of frequency (TCF), were measured using thin-film aluminum interdigital electrodes patterned on the upper film surface. The presence of the SiO2 initially stiffened the substrate surfaces before softening the surface with increasing thickness. The SAW propagation loss values showed a minimum at film-thickness to acoustic-wavelength ratios (t/λ) in the 0.02 to 0.08 region. The TCF improved but Cm/C0 decreased with increasing t/λ ratio
Keywords :
Rayleigh waves; acoustic materials; dielectric thin films; interdigital transducers; lithium compounds; silicon compounds; sputtered coatings; surface acoustic wave transducers; 30 MHz to 1 GHz; 500 to 2000 nm; LiNbO3; LiTaO3; Rayleigh waves; SAW propagation characteristics; SAW velocity; SiO2; SiO2-LiNbO3; SiO2-LiTaO3; Y-X cut substrates; capacitance ratio; leaky waves; patterned electrodes; propagation loss; sputtered thin-film SiO2; temperature coefficient of frequency; thin-film Al interdigital electrodes; upper film surface; Acoustic measurements; Acoustic propagation; Acoustic waves; Frequency measurement; Propagation losses; Semiconductor thin films; Silicon compounds; Sputtering; Substrates; Surface acoustic waves;
Conference_Titel :
Ultrasonics Symposium, 1995. Proceedings., 1995 IEEE
Conference_Location :
Seattle, WA
Print_ISBN :
0-7803-2940-6
DOI :
10.1109/ULTSYM.1995.495595
