Patent ID: 7327071

Claim:
A surface acoustic wave device comprising: a piezoelectric substrate made of one of LiTaO 3 or LiNbO 3 and having an electromechanical coefficient of at least about 15%; at least one electrode disposed on the piezoelectric substrate and defined by a laminate having a metal layer defining a primary metal layer made of a metal having a density greater than that of Al or an alloy primarily composed of the metal and a metal layer which is laminated on the primary metal layer and which is made of another metal; a first SiO 2 layer disposed in a remaining area other than that at which said at least one electrode is located and having a thickness approximately equal to that of the at least one electrode; a second SiO 2 layer disposed to cover the at least one electrode and the first SiO 2 layer; and a silicon nitride compound layer disposed on the second SiO 2 layer; wherein the density of the at least one electrode is at least about 1.5 times that of the first SiO 2 layer.