Elliptical structure for bulk acoustic wave resonator

Abstract

An elliptical-shaped resonator device. The device includes a bottom metal plate, a piezoelectric layer overlying the bottom metal plate, and a top metal plate overlying the piezoelectric layer. The top metal plate, the piezoelectric layer, and the bottom metal plate are characterized by an elliptical shape having a horizontal diameter (dx) and a vertical diameter (dy), which can be represented as ellipse ratio R=dx/dy. Using the elliptical structure, the resulting bulk acoustic wave resonator (BAWR) can exhibit equivalent or improved insertion loss, higher coupling coefficient, and higher quality factor compared to conventional polygon-shaped resonators.

What is claimed is: 
     
         1 . An elliptical-shaped resonator circuit device, the device comprising:
 a substrate   a piezoelectric layer overlying the substrate, the piezoelectric layer having a micro-via;   a bottom metal plate underlying the piezoelectric layer;   a backside metal interconnect underlying the piezoelectric layer and coupled to the bottom metal plate;   a top metal plate overlying the piezoelectric layer; and   a topside metal interconnect overlying the piezoelectric layer and coupled to the backside metal interconnect through the micro-via;   wherein the top metal plate, the piezoelectric layer, and the bottom metal plate are characterized by an elliptical shape having a horizontal diameter (dx) and a vertical diameter (dy), which can be represented as ellipse ratio R=dx/dy.   
     
     
         2 . The device of  claim 1  wherein the ellipse ratio R ranges from about 1.20 to about 2.0. 
     
     
         3 . The device of  claim 1  wherein the bottom metal plate and top metal plate include molybdenum (Mo), ruthenium (Ru), or tungsten (W), Aluminum-Copper (AlCu). 
     
     
         4 . The device of  claim 1  wherein the piezoelectric layer includes materials or alloys having at least one of the following: AlN, AlGaN, GaN, InN, InGaN, AlInN, AlInGaN, ScAlN, ScGaN, AlScYN, and BN. 
     
     
         5 . The device of  claim 1  further comprising one or more pillar-type energy confinement features (ECFs) coupled to the top metal plate or the bottom metal plate; wherein the one or more pillar-type ECFs comprises a dielectric material, a metal material, or a combination of dielectric and metal materials. 
     
     
         6 . The device of  claim 1  further comprising one or more cavity-type energy confinement features (ECFs) configured within the top metal plate or the bottom metal plate. 
     
     
         7 . An RF filter circuit device, the device comprising:
 a substrate member;   a dielectric passivation layer overlying the substrate member;   a plurality of elliptical-shaped resonator devices overlying the substrate member and configured within the dielectric passivation layer, each of the elliptical shaped resonators comprising
 a piezoelectric layer overlying the bottom metal plate, the piezoelectric layer having a micro-via; 
 a bottom metal plate underlying the piezoelectric layer; 
 a backside metal interconnect underlying the piezoelectric layer and coupled to the bottom metal plate; 
 a top metal plate overlying the piezoelectric layer; and 
 a topside metal interconnect overlying the piezoelectric layer and coupled to the backside metal interconnect through the micro-via; 
 wherein the top metal plate, the piezoelectric layer, and the bottom metal plate are characterized by an elliptical shape having a horizontal diameter (dx) and a vertical diameter (dy), which can be represented as ellipse ratio R=dx/dy; and 
   wherein each of the plurality of elliptical-shaped resonator devices is coupled to at least one other resonator in the plurality of elliptical-shaped resonator devices.   
     
     
         8 . The device of  claim 7  wherein the ellipse ratio R ranges from about 1.20 to about 2.00. 
     
     
         9 . The device of  claim 7  wherein the substrate member is selected from a silicon substrate, a sapphire substrate, silicon carbide substrate, a GaN bulk substrate, a GaN template, an AlN bulk substrate, an AlN template, Al x Ga 1-x N templates, engineered substrates such as silicon on insulator (SOI), and polycrystalline AlN templates. 
     
     
         10 . The device of  claim 7  wherein the dielectric passivation layer includes silicon oxide, silicon nitride, aluminum nitride, or aluminum oxide materials. 
     
     
         11 . The device of  claim 7  wherein the bottom metal plate and top metal plate include molybdenum (Mo), ruthenium (Ru), tungsten (W), or Aluminum Copper (AlCu) materials. 
     
     
         12 . The device of  claim 7  wherein the piezoelectric layer includes materials or alloys having at least one of the following: AlN, AlGaN, GaN, InN, InGaN, AlInN, AlInGaN, ScAlN, ScGaN, AlScYN, and BN. 
     
     
         13 . The device of  claim 7  wherein the micro-via includes molybdenum (Mo), ruthenium (Ru), tungsten (W), or Aluminum Copper (AlCu) materials. 
     
     
         14 . The device of  claim 7  further comprising one or more pillar-type energy confinement features (ECFs) coupled to the top metal plate or the bottom metal plate; wherein the one or more pillar-type ECFs comprises a dielectric material, a metal material, or a combination of dielectric and metal materials. 
     
     
         15 . The device of  claim 7  further comprising one or more cavity-type energy confinement features (ECFs) configured within the top metal plate or the bottom metal plate. 
     
     
         16 . An RF filter circuit device, the device comprising:
 a substrate member;   a dielectric passivation layer overlying the substrate member;   a plurality of elliptical-shaped resonator devices overlying the substrate member and configured within the dielectric passivation layer, each of the elliptical shaped resonators comprising
 a piezoelectric layer overlying the bottom metal plate, the piezoelectric layer having a micro-via; 
 a bottom metal plate underlying the piezoelectric layer; 
 a backside metal interconnect underlying the piezoelectric layer and coupled to the bottom metal plate; 
 a top metal plate overlying the piezoelectric layer; 
 a topside metal interconnect overlying the piezoelectric layer and coupled to the backside metal interconnect through the micro-via; 
 one or more pillar-type energy confinement features (ECFs) coupled to the top metal plate or the bottom metal plate, wherein the one or more pillar-type ECFs comprises a dielectric material, a metal material, or a combination of dielectric and metal materials; and 
 one or more cavity-type energy confinement features (ECFs) configured within the top metal plate or the bottom metal plate; 
 wherein the top metal plate, the piezoelectric layer, and the bottom metal plate are characterized by an elliptical shape having a horizontal diameter (dx) and a vertical diameter (dy), which can be represented as ellipse ratio R=dx/dy; and 
   wherein each of the plurality of elliptical-shaped resonator devices is coupled to at least one other resonator in the plurality of elliptical-shaped resonator devices.   
     
     
         17 . The device of  claim 16  wherein the ellipse ratio R ranges from about 1.20 to about 2.00. 
     
     
         18 . The device of  claim 16  wherein the substrate member is selected from a silicon substrate, a sapphire substrate, silicon carbide substrate, a GaN bulk substrate, a GaN template, an AlN bulk substrate, an AlN template, Al x Ga 1-x N templates, engineered substrates such as silicon on insulator (SOI), and polycrystalline AlN templates; and
 wherein the dielectric passivation layer includes silicon oxide, silicon nitride, aluminum nitride, or aluminum oxide materials. 
 
     
     
         19 . The device of  claim 16  wherein the bottom metal plate and top metal plate include molybdenum (Mo), ruthenium (Ru), tungsten (W), or Aluminum Copper (AlCu) materials;
 wherein the piezoelectric layer includes materials or alloys having at least one of the following: AlN, AlGaN, GaN, InN, InGaN, AlInN, AlInGaN, ScAlN, ScGaN, AlScYN, and BN; and 
 wherein the micro-via includes molybdenum (Mo), ruthenium (Ru), tungsten (W), or Aluminum Copper (AlCu) materials. 
 
     
     
         20 . The device of  claim 16  wherein the piezoelectric layer includes materials or alloys having at least one of the following: AlN, AlGaN, GaN, InN, InGaN, AlInN, AlInGaN, ScAlN, ScGaN, AlScYN, and BN.