Thin film piezoelectric resonator and manufacturing process thereof
A thin film piezoelectric resonator includes a substrate having a cavity, and a resonance portion located on the substrate and right above the cavity. The resonance portion includes a lower electrode layer located at a side of the cavity, an upper electrode layer opposite to the lower electrode layer, and a piezoelectric thin film located between the upper electrode layer and the lower electrode layer. A side of the piezoelectric thin film and a side of the lower electrode layer are located in a common plane.
1. A thin film piezoelectric resonator, comprising:
a substrate having a cavity; and
a resonance portion located on the substrate and right above the cavity,
wherein the resonance portion includes a lower electrode layer, an upper electrode layer opposite to the lower electrode layer, a first piezoelectric thin film located on the lower electrode layer, and a second piezoelectric thin film covering a side of the lower electrode and a top and a side of the first piezoelectric thin film,
wherein a side of the first piezoelectric thin film and a side of the lower electrode layer are located in a common plane, and the upper electrode layer is located on a side and a part of a top of the second piezoelectric thin film.
2. The thin film piezoelectric resonator according to claim 1 , wherein the second piezoelectric thin film has a thickness smaller than that of the first piezoelectric thin film.
3. The thin film piezoelectric resonator according to claim 1 , further comprising a conductive layer located on the substrate,
wherein a part of the lower electrode layer is located on the conductive layer.
4. The thin film piezoelectric resonator according to claim 3 , further comprising an electrode pad located on the substrate,
wherein a part of the electrode pad is located on the conductive layer.
5. The thin film piezoelectric resonator according to claim 1 , wherein the cavity is a hole penetrated from a surface of the substrate to another surface thereof.
6. The thin film piezoelectric resonator according to claim 1 , wherein the cavity is a hollow formed at a surface of the substrate.
7. A thin film piezoelectric resonator, comprising:
a substrate having a cavity; and
a resonance portion located on the substrate and right above the cavity,
wherein the resonance portion includes a lower electrode layer, an upper electrode layer opposite to the lower electrode layer, a first piezoelectric thin film located on the lower electrode layer, and a second piezoelectric thin film covering a top and a first side of the first piezoelectric thin film and a first side of the lower electrode,
wherein the first side of the first piezoelectric thin film and the first side of the lower electrode layer are located in a first common plane, and a second side of the first piezoelectric thin film and a first side of the second piezoelectric thin film are located in a second common plane.
8. The thin film piezoelectric resonator according to claim 7 , wherein the second piezoelectric thin film has a thickness smaller than that of the first piezoelectric thin film.
9. The thin film piezoelectric resonator according to claim 7 , further comprising a conductive layer located on the substrate,
wherein a part of the lower electrode layer is located on the conductive layer.
10. The thin film piezoelectric resonator according to claim 7 , wherein the cavity is a hole penetrated from a surface of the substrate to another surface thereof.
11. The thin film piezoelectric resonator according to claim 7 , wherein the cavity is a hollow formed at a surface of the substrate.