Patent ID: 7956511

Claim:
A surface acoustic wave device comprising: a piezoelectric substrate including a plurality of grooves provided in an upper surface thereof and which is made of an LiNbO 3 substrate; and an IDT including a plurality of electrode fingers made of a metal material which is filled in the plurality of grooves in the upper surface of the piezoelectric substrate; wherein the metal material is made of a metal selected from the group consisting of Ag, Ni, and Cr or an alloy primarily including at least one of Ag, Ni, and Cr; and when a wavelength of a surface acoustic wave is represented by λ, an electrode thickness of the IDT and θ of Euler angles (0°±10°, θ, 0°±10°) of the LiNbO 3 substrate are one of combinations shown in Table 1: TABLE 1 ELECTRODE MATERIAL ELECTRODE THICKNESS EULER ANGLE θ Ag 0.02λ ≦ Ag ≦ 0.04λ 70° ≦ θ ≦ 145° Ag 0.04λ < Ag ≦ 0.08λ 70° ≦ θ ≦ 142° Ni 0.04λ ≦ Ni ≦ 0.08λ 70° ≦ θ ≦ 153° Cr 0.02λ ≦ Cr ≦ 0.04λ 70° ≦ θ ≦ 145° Cr 0.04λ < Cr ≦ 0.08λ 70° ≦ θ ≦ 152° .