Acoustic wave device with multi-layer interdigital transducer electrode

An acoustic wave filter with reduced insertion loss, the acoustic wave filter comprising:

• an acoustic wave resonator that includes a piezoelectric layer, a temperature compensation layer, and an interdigital transducer electrode positioned between the piezoelectric layer and at least a portion of the temperature compensation layer, the interdigital transducer electrode including a first interdigital transducer electrode layer and a second interdigital transducer electrode layer, the first interdigital transducer electrode layer being positioned between the second interdigital transducer electrode layer and the piezoelectric layer, the second interdigital transducer electrode layer including aluminum and having a thickness of at least 200 nanometers;
• and
• a plurality of additional acoustic wave resonators, the acoustic wave resonator and the plurality of additional acoustic wave resonators together configured as a band pass filter with a radio frequency pass band, and the thickness of the second interdigital transducer electrode layer causing insertion loss in the radio frequency pass band to be reduced.

A method of filtering a radio frequency signal with reduced insertion loss, the method comprising:

• providing a radio frequency signal to a surface acoustic wave filter, the surface acoustic wave filter including a temperature compensated surface acoustic wave resonator, the temperature compensated surface acoustic wave resonator including an interdigital transducer electrode on a piezoelectric layer and a temperature compensation layer over the interdigital transducer electrode, the interdigital transducer electrode including a first interdigital transducer layer and a second interdigital transducer layer positioned over the first interdigital transducer layer, the second interdigital transducer layer including an aluminum layer having a thickness of at least 200 nanometers, the second interdigital transducer electrode layer being sufficiently thick to saturate insertion loss improvement associated with the thickness of the second interdigital transducer electrode layer;
• and
• filtering the radio frequency signal with the surface acoustic wave filter.