Acoustic wave device with multi-layer piezoelectric substrate

A surface acoustic wave device comprising:

• a support layer;
• a quartz layer over the support layer, the quartz layer with a first Euler angle φ in a range from 40° to 50°, a second Euler angle θ in a range from 85° to 95°, and a third Euler angle ψ in a range of 85° to 95°;
• a lithium based piezoelectric layer over the quartz layer, the lithium based piezoelectric layer having a lower thermal conductivity than the support layer;
• and
• an interdigital transducer electrode over the lithium based piezoelectric layer, the surface acoustic wave device configured to generate a surface acoustic wave.

A surface acoustic wave device comprising:

• a z-propagation quartz layer having a first Euler angle φ in a range from 40° to 50°, a second Euler angle θ in a range from 85° to 95°, and a third Euler angle ψ in a range of 85° to 95°;
• a support layer below the z-propagation quartz layer, the support layer having a first thermal conductivity that is higher than a second thermal conductivity of the z-propagation quartz layer;
• a lithium based piezoelectric layer over the z-propagation quartz layer, the lithium based piezoelectric layer having a third thermal conductivity that is less than the first thermal conductivity of the support layer;
• and
• an interdigital transducer electrode over the lithium based piezoelectric layer, the surface acoustic wave device configured to generate a surface acoustic wave.