Surface acoustic wave device

Abstract

A surface acoustic wave device is provided. The surface acoustic wave device includes a piezoelectric substrate and an IDT which is disposed on the piezoelectric substrate and made of Al or an alloy containing Al as a main component and using an SH wave as an excitation wave, wherein the piezoelectric substrate is a rotated Y-cut quartz plate having a cut angle θ set to a range of −64.0<θ<−49.3° rotated counterclockwise from a Z crystalline axis and a propagation direction of a surface acoustic wave set to a direction of 90°±5° with respect to an X crystalline axis, wherein, when a wavelength of an excited surface acoustic wave is denoted by λ, an electrode film thickness H/λ normalized with wavelength of the IDT is set to a range of 0.04<H/λ<0.12, and wherein, when a line occupancy rate mr of electrode fingers constituting the IDT is defined to be electrode finger width/(electrode finger width+electrode finger spacing), the line occupancy rate mr is set to a range of 0.53≦mr≦0.65.

1 . A surface acoustic wave device comprising a piezoelectric substrate and an IDT which is disposed on the piezoelectric substrate and made of Al or an alloy containing Al as a main component and using an SH wave as an excitation wave, 
 wherein the piezoelectric substrate is a rotated Y-cut quartz plate having a cut angle θ set to a range of −64.0°<74 <−49.3° rotated counterclockwise from a Z crystalline axis and a propagation direction of a surface acoustic wave set to a direction of 90°±5° with respect to an X crystalline axis,    wherein, when a wavelength of an excited surface acoustic wave is denoted by λ, an electrode film thickness H/λ normalized with wavelength of the IDT is set to a range of 0.04<H/λ<0.12, and    wherein, when a line occupancy rate mr of electrode fingers constituting the IDT is defined to be electrode finger width/(electrode finger width+electrode finger spacing), the line occupancy rate mr is set to a range of 0.53≦mr≦0.65.    
   
   
       2 . A surface acoustic wave device comprising a piezoelectric substrate and an IDT which is disposed on the piezoelectric substrate and made of Al or an alloy containing Al as a main component and using an SH wave as an excitation wave, 
 wherein the piezoelectric substrate is a rotated Y-cut quartz plate having a cut angle θ set to a range of −64.0°<θ<−49.3° rotated counterclockwise from a Z crystalline axis and a propagation direction of a surface acoustic wave set to a direction of 90°±5° with respect to an X crystalline axis,    wherein, when a wavelength of an excited surface acoustic wave is denoted by λ, an electrode film thickness H/λ normalized with wavelength of the IDT is set to a range of 0.04<H/λ<0.12, and    wherein, when a line occupancy rate mr of electrode fingers constituting the IDT is defined to be electrode finger width/(electrode finger width+electrode finger spacing), the line occupancy rate mr is set to a range of 0.55≦mr≦0.68.    
   
   
       3 . A surface acoustic wave device comprising a piezoelectric substrate and an IDT which is disposed on the piezoelectric substrate and made of Al or an alloy containing Al as a main component and using an SH wave as an excitation wave, 
 wherein the piezoelectric substrate is a rotated Y-cut quartz plate having a cut angle θ set to a range of −64.0°<θ<−49.3° rotated counterclockwise from a Z crystalline axis and a propagation direction of a surface acoustic wave set to a direction of 90°±5° with respect to an X crystalline axis,    wherein, when a wavelength of an excited surface acoustic wave is denoted by λ, an electrode film thickness H/λ normalized with wavelength of the IDT is set to a range of 0.04<H/λ<0.12, and    wherein, when a line occupancy rate mr of electrode fingers constituting the IDT is defined to be electrode finger width/(electrode finger width+electrode finger spacing), the line occupancy rate mr is set to a range of 0.55≦mr≦0.65.    
   
   
       4 . The surface acoustic wave device according to  claim 1 , wherein the cut angle θ is set to a range of −61.4°<θ<−51.1°.  
   
   
       5 . The surface acoustic wave device according to  claim 1 , wherein the electrode film thickness H/λ is set to a range of 0.05<H/λ<0.10.  
   
   
       6 . The surface acoustic wave device according to  claim 1 , wherein the electrode film thickness H/λ is set to a range of 0.04≦H/λ≦0.08.  
   
   
       7 . A surface acoustic wave device comprising a piezoelectric substrate and an IDT which is disposed on the piezoelectric substrate and made of Al or an alloy containing Al as a main component and using an SH wave as an excitation wave, 
 wherein the piezoelectric substrate is a rotated Y-cut quartz plate having a cut angle θ set to a range of −64.0°<θ<−49.3° rotated counterclockwise from a Z crystalline axis and a propagation direction of a surface acoustic wave set to a direction of 90°±5° with respect to an X crystalline axis, and    wherein grooves are formed in spaces between electrode fingers of the IDT, and when a depth of the grooves and a film thickness of a metal film are denoted by Hp and Hm, respectively, an electrode film thickness H/λ normalized with wavelength of the IDT is set to a range of 0.04<H/λ<0.12 (H=Hp+Hm).    
   
   
       8 . A module apparatus or an oscillating circuit using the surface acoustic wave device according to  claim 1 .  
   
   
       9 . The surface acoustic wave device according to  claim 2 , wherein the cut angle θ is set to a range of −61.4°<θ<−51.1°.  
   
   
       10 . The surface acoustic wave device according to  claim 3 , wherein the cut angle θ is set to a range of −61.4°<θ<−51.1°.  
   
   
       11 . The surface acoustic wave device according to  claim 2 , wherein the electrode film thickness H/λ is set to a range of 0.05<H/λ<0.10.  
   
   
       12 . The surface acoustic wave device according to  claim 3 , wherein the electrode film thickness H/λ is set to a range of 0.05<H/λ<0.10.  
   
   
       13 . The surface acoustic wave device according to  claim 2 , wherein the electrode film thickness H/λ is set to a range of 0.04≦H/λ≦0.08.  
   
   
       14 . The surface acoustic wave device according to  claim 3 , wherein the electrode film thickness H/λ is set to a range of 0.04≦H/λ≦0.08.  
   
   
       15 . A module apparatus or an oscillating circuit using the surface acoustic wave device according to  claim 2 .  
   
   
       16 . A module apparatus or an oscillating circuit using the surface acoustic wave device according to  claim 3 .  
   
   
       17 . A module apparatus or an oscillating circuit using the surface acoustic wave device according to  claim 7.