Multilayer piezoelectric substrate

An electronics module comprising:

• at least one radio frequency filter including at least one acoustic wave device, the at least one acoustic wave device including
• a layered substrate including a piezoelectric material layer bonded to a second material layer including a material having a higher thermal conductivity than the piezoelectric material layer, the piezoelectric material layer including a multilayer piezoelectric substrate including three layers, a central layer of the three layers having a largest electromechanical coupling coefficient among the three layers,
• interdigital transducer electrodes disposed on a surface of the piezoelectric material layer,
• contact pads disposed on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes,
• external bond pads disposed on the second material layer and configured to electrically connect the acoustic wave device to a circuit board, and
• conductive vias passing through the layered substrate and providing electrical contact between the contact pads and external bond pads.

An acoustic wave device comprising:

• a layered substrate including a piezoelectric material layer bonded to a second material layer including a material having a higher thermal conductivity than the piezoelectric material layer;
• interdigital transducer electrodes disposed on a surface of the piezoelectric material layer;
• a cavity defined above the interdigital transducer electrodes by walls and a cap including a dielectric material;
• contact pads disposed on the piezoelectric material layer within the cavity and in electrical contact with the interdigital transducer electrodes;
• external bond pads disposed on the cap on an opposite side of the cap from the cavity;
• and
• conductive vias passing through the cap and providing electrical contact between the contact pads and external bond pads.

An acoustic wave device comprising:

• a layered substrate including a piezoelectric material layer bonded to a second material layer including a material having a higher thermal conductivity than the piezoelectric material layer;
• interdigital transducer electrodes disposed on a surface of the piezoelectric material layer;
• contact pads disposed on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes;
• external bond pads disposed on the second material layer and configured to electrically connect the acoustic wave device to a circuit board;
• and
• conductive vias passing through the layered substrate and providing electrical contact between the contact pads and external bond pads, each of the conductive vias passing in a straight line through the layered substrate from the contact pads to the external bond pads.