Patent ID: 9136458
Filing Date: 2015-09-15
Classification: H01L,H03H

Abstract:
1. An elastic wave device comprising: an interdigital transducer (IDT) electrode in contact with a piezoelectric substrate, the IDT electrode including a first bus bar electrode, a second bus bar electrode facing the first bus bar electrode, first electrode fingers extending from the first bus bar electrode toward the second bus bar electrode, and second electrode fingers extending from the second bus bar electrode toward the first bus bar electrode, the first electrode fingers alternately disposed with the second electrode fingers, the piezoelectric substrate including a bus bar electrode region including one of the first bus bar electrode and the second bus bar electrode, an alternately disposed region where the first electrode fingers are alternately disposed with the second electrode fingers, and an intermediate region including one of the first electrode fingers and the second electrode fingers; a first dielectric film formed in at least part of the intermediate region and in contact with an upper surface of the IDT electrode, the first dielectric film including a medium in which an acoustic velocity of a transverse wave propagating in the first dielectric film is lower than an acoustic velocity of a main elastic wave of the alternately disposed region; and a second dielectric film distinct from the first dielectric film formed in at least part of the alternately disposed region and in contact with an upper surface of the IDT electrode, the second dielectric film including a medium in which an acoustic velocity of a transverse wave propagating in the second dielectric film is higher than an acoustic velocity of a main elastic wave in the intermediate region.