Multilayer piezoelectric substrate surface acoustic wave device with spurious shifting

Abstract

An acoustic wave device is disclosed. The acoustic wave device is configured to generate a surface acoustic wave having a wavelength L. The acoustic wave device can include a piezoelectric layer. The piezoelectric layer has a thickness in a range of 0.1 L to 0.3 L. The acoustic wave device can include an interdigital transducer electrode that is positioned over the piezoelectric layer, and a support substrate that is bonded to the piezoelectric layer such that the piezoelectric layer is positioned between the interdigital transducer electrode and the support substrate. The support substrate has a cut angle configured to provide a velocity of the surface acoustic wave calculated by multiplying the wavelength L by a particular frequency to be greater than 4800 m/s.

What is claimed is: 
     
         1 . An acoustic wave device configured to generate a surface acoustic wave having a wavelength L, the acoustic wave device comprising:
 a piezoelectric layer, the piezoelectric layer having a thickness in a range of 0.1 L to 0.3 L;   an interdigital transducer electrode over the piezoelectric layer; and   a support substrate bonded to the piezoelectric layer such that the piezoelectric layer is positioned between the interdigital transducer electrode and the support substrate, the support substrate having a cut angle configured to provide a velocity of the surface acoustic wave calculated by multiplying the wavelength L by a particular frequency to be greater than 4800 m/s.   
     
     
         2 . The acoustic wave device of  claim 1  wherein the piezoelectric layer is a lithium tantalate layer. 
     
     
         3 . The acoustic wave device of  claim 2  wherein the lithium tantalate layer is a 42±10° Y-X lithium tantalate layer. 
     
     
         4 . The acoustic wave device of  claim 1  wherein the cut angle of the support substrate is configured to provide the velocity of the surface acoustic wave to be greater than 5000 m/s. 
     
     
         5 . The acoustic wave device of  claim 4  wherein the cut angle of the support substrate is configured to provide the velocity of the surface acoustic wave to be between 5060 m/s and 5800 m/s. 
     
     
         6 . The acoustic wave device of  claim 1  wherein the cut angle of the support substrate is in a range of, in Euler angle (φ, θ, ψ), (90±15°, 90±15°, 90±15°). 
     
     
         7 . The acoustic wave device of  claim 1  wherein the cut angle of the support substrate is in a range of, in Euler angle (φ, θ, ψ), (45±15°, 90±15°, 90±15°°). 
     
     
         8 . The acoustic wave device of  claim 1  wherein the cut angle of the support substrate is in a range of, in Euler angle (φ, θ, ψ), (45±15°, 54.74±15°, 60±15°). 
     
     
         9 . The acoustic wave device of  claim 1  further comprising an adhesion layer between the piezoelectric layer and the support substrate. 
     
     
         10 . The acoustic wave device of  claim 1  further comprising a polycrystalline silicon layer or an amorphous silicon layer between the piezoelectric layer and the support substrate. 
     
     
         11 . The acoustic wave device of  claim 1  further comprising a silicon nitride layer or an aluminum nitride layer between the piezoelectric layer and the support substrate. 
     
     
         12 . The acoustic wave device of  claim 1  further comprising a polycrystalline silicon layer or an amorphous silicon layer, and a silicon nitride layer or an aluminum nitride layer between the piezoelectric layer and the support substrate. 
     
     
         13 . An acoustic wave device comprising:
 a piezoelectric layer;   an interdigital transducer electrode over the piezoelectric layer; and   a support substrate bonded to the piezoelectric layer such that the piezoelectric layer is positioned between the interdigital transducer electrode and the support substrate, the support substrate having a cut angle in a range of, in Euler angle (φ, θ, ψ), (90±15°, 90±15°, 90±15°), (45±15°, 90±15°, 90±15°°), or (45±15°, 54.74±15°, 60±15°).   
     
     
         14 . The acoustic wave device of  claim 13  wherein the piezoelectric layer is a lithium tantalate layer. 
     
     
         15 . The acoustic wave device of  claim 14  wherein the lithium tantalate layer is a 42±10° ° Y-X lithium tantalate layer. 
     
     
         16 . The acoustic wave device of  claim 13  wherein the acoustic wave device configured to generate a surface acoustic wave having a wavelength L, and the piezoelectric layer has a thickness in a range of 0.1 L to 0.3 L. 
     
     
         17 . The acoustic wave device of  claim 13  wherein the cut angle of the support substrate is configured to provide a velocity of a surface acoustic wave generated by the acoustic wave device to be between 5060 m/s and 5800 m/s. 
     
     
         18 . The acoustic wave device of  claim 13  further comprising a polycrystalline silicon layer or an amorphous silicon layer between the piezoelectric layer and the support substrate. 
     
     
         19 . The acoustic wave device of  claim 13  further comprising a silicon nitride layer or an aluminum nitride layer between the piezoelectric layer and the support substrate. 
     
     
         20 . The acoustic wave device of  claim 13  further comprising a polycrystalline silicon layer or an amorphous silicon layer, and a silicon nitride layer or an aluminum nitride layer between the piezoelectric layer and the support substrate.