Patent ID: 6914498

Claim:
A surface acoustic wave device comprising: a LiTaO 3 substrate having Euler angles (0±3°, 110° to 150°, 0±3°); at least one IDT disposed on the LiTaO 3 substrate and which primarily includes Ag; and a SiO 2 film arranged on the LiTaO 3 substrate so as to cover the at least one IDT; wherein the film thickness H/λ (H represents a film thickness and λ represents a wavelength of a surface acoustic wave) of the IDT is within the range of about 0.01 to about 0.08, and the combination of the normalized film thickness of the SiO 2 and the Euler angles of the LiTaO 3 substrate is any one of those indicated by (a) to (f) in the following Table: SiO 2 film thickness Euler angles of LiTaO 3 (°) (a) 0.15 to 0.18 0 ± 3, 113 to 150, 0 ± 3 (b) 0.18 to 0.23 0 ± 3, 115 to 145, 0 ± 3 (c) 0.23 to 0.28 0 ± 3, 115 to 145, 0 ± 3 (d) 0.28 to 0.33 0 ± 3, 114 to 143, 0 ± 3 (e) 0.33 to 0.38 0 ± 3, 112 to 142, 0 ± 3 (f) 0.38 to 0.40 0 ± 3, 110 to 140, 0 ± 3.