Abstract: A SAW device comprises a single crystal piezo-electric strate (made, for example, of LiTaO3 or LiNbO3), and an interdigital transducer (IDT) formed of a material mainly containing Al and disposed on the piezo-electric substrate. The piezo-electric strate contains an additive (for example, Fe, Mn, Cu, Ti), and an orientation rotated by an angle in a range of 42° to 48° (more preferably 46°±0.3°) from a Y-axis toward a Z-axis about an X-axis. The IDT presents a normalized thickness h/? (h: thickness of electrode, and ?: spacing between digits of the IDT) of 7% to 11%. A more appropriate substrate cut angle can be shown for the SAW device which employs a piezo-electric substrate containing an additive, to improve the electric characteristics thereof.

Abstract: A surface acoustic wave element includes a thin film electrode composed of monocrystal aluminum disposed on a piezoelectric substrate. At least one metal of Cu, Ta, W, and Ti is segregated in the thin film electrode composed of monocrystal aluminum. In this surface acoustic wave element, segregation of Cu or the like occurs in the thin film electrode. Such segregation is effective to reduce the occurrence of cracks on the piezoelectric substrate during ultrasonic wave connection for flip chip mounting. That is, because the occurrence of cracks on the piezoelectric substrate is reduced, tolerance against the ultrasonic vibration is advantageously improved in the surface acoustic wave element.

Abstract: A SAW device comprises a single crystal piezo-electric strate (made, for example, of LiTaO3 or LiNbO3), and an interdigital transducer (IDT) formed of a material mainly containing Al and disposed on the piezo-electric substrate. The piezo-electric strate contains an additive (for example, Fe, Mn, Cu, Ti), and an orientation rotated by an angle in a range of 42° to 48°re preferably 46°±0.3°) from a Y-axis toward a Z-axis about an axis. The IDT presents a normalized thickness h/? (h: thickness electrode, and ?: spacing between digits of the IDT) of 7% to 11%. A more appropriate substrate cut angle can be shown for the device which employs a piezo-electric substrate containing an additive, to improve the electric characteristics thereof.

Abstract: A surface acoustic wave element, a surface acoustic wave device, a duplexer, and a method of making a surface acoustic wave element which significantly restrain characteristics from deteriorating are provided. The surface acoustic wave element in accordance with the present invention comprises a piezoelectric substrate, and an IDT electrode formed on the piezoelectric substrate, whereas the piezoelectric substrate has a volume resistivity of not less than 3.6×1010 ?·cm and not more than 1.5×1014 ?·cm. This surface acoustic wave element comprises the piezoelectric substrate having a low volume resistivity, whereas the volume resistivity is reduced to 1.5×1014 ?·cm or less. Therefore, discharging is restrained from occurring between IDT electrodes, whereby characteristics are significantly kept from deteriorating. Also, since the volume resistivity of the piezoelectric substrate is not less than 3.6×1010 ?·cm, the IDT electrodes are significantly prevented from short-circuiting with each other.

Abstract: A surface acoustic wave element includes a thin film electrode composed of monocrystal aluminum disposed on a piezoelectric substrate. At least one metal of Cu, Ta, W, and Ti is segregated in the thin film electrode composed of monocrystal aluminum. In this surface acoustic wave element, segregation of Cu or the like occurs in the thin film electrode. Such segregation is effective to reduce the occurrence of cracks on the piezoelectric substrate during ultrasonic wave connection for flip chip mounting. That is, because the occurrence of cracks on the piezoelectric substrate is reduced, tolerance against the ultrasonic vibration is advantageously improved in the surface acoustic wave element.