ELASTIC WAVE ELEMENT AND ELASTIC WAVE DEVICE EMPLOYING SAME

摘要

An SAW element (1) comprises: a substrate (3); an IDT electrode (5), which is positioned upon the upper face (3a) of the substrate (3) and is formed from either aluminum (Al) or an alloy of which aluminum (Al) is a primary constituent; a first film (9) which is positioned upon the upper face of the IDT electrode (5); and a protective layer (11), which covers the IDT electrode (5) whereon the first film (9) is positioned and the portion of the substrate (3) which is not covered by the IDT electrode (5), wherein the thickness (t) from the upper face (3a) of the substrate (3) is greater than the total thickness (e) of the IDT electrode (5) and the first film (9), and whereof a silicon oxide is a component. The first film (9) has as a primary constituent a material which has a greater audio impedance than the material (aluminum (Al) or the alloy of which aluminum (Al) is the primary constituent) of the IDT electrode (5) and the silicon oxide, and which has a slower speed of propagation of elastic waves than the material of the IDT electrode (5) and the silicon oxide.