Bragg mirror and BAW resonator with a high quality factor on the bragg mirror
First Claim
1. A Bragg mirror, comprising:
- a first conductive layer;
a first dielectric layer on the first conductive layer;
a second conductive layer between a substrate and the first conductive layer and electrically connected to the first conductive layer, the second conductive layer having an electric conductivity greater than that of the first conductive layer and an acoustic impedance different from that of the first conductive layer.
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Accused Products
Abstract
A method for manufacturing a bulk acoustic wave resonator, each resonator including: above a substrate, a piezoelectric resonator, and next to the piezoelectric resonator, a contact pad connected to an electrode of the piezoelectric resonator; and, between the piezoelectric resonator and the substrate, a Bragg mirror including at least one conductive layer extending between the pad and the substrate and at least one upper silicon oxide layer extending between the pad and the substrate, the method including the steps of: depositing the upper silicon oxide layer; and decreasing the thickness unevenness of the upper silicon oxide layer due to the deposition method, so that this layer has a same thickness to within better than 2%, and preferably to within better than 1%, at the level of each pad.
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Citations
19 Claims
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1. A Bragg mirror, comprising:
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a first conductive layer; a first dielectric layer on the first conductive layer; a second conductive layer between a substrate and the first conductive layer and electrically connected to the first conductive layer, the second conductive layer having an electric conductivity greater than that of the first conductive layer and an acoustic impedance different from that of the first conductive layer. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A bulk acoustic wave resonator, comprising:
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a substrate; a Bragg mirror on the substrate, the Bragg mirror having a first conductive layer on the substrate and a first dielectric layer on the first conductive layer; a piezoelectric resonator on the first dielectric layer, the piezoelectric resonator having a first electrode; a first contact pad adjacent the piezoelectric resonator on the first dielectric layer, the first contact pad coupled to the first electrode of the piezoelectric resonator; and a second conductive layer between the substrate and the first conductive layer and electrically connected to the first conductive layer, the second conductive layer having an electric conductivity greater than that of the first conductive layer and an acoustic impedance different from that of the first conductive layer, wherein the first conductive layer and the second conductive layer extend from a first region that is between the first contact pad and the substrate to a second region that is between the piezoelectric resonator and the substrate. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A bulk acoustic wave resonator, comprising:
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a substrate; a Bragg mirror on the substrate, the Bragg mirror having a first conductive layer on the substrate and a first dielectric layer on the first conductive layer; a piezoelectric resonator on the first dielectric layer, the piezoelectric resonator having a first electrode; a first contact pad adjacent the piezoelectric resonator on the first dielectric layer, the first contact pad being coupled to the first electrode of the piezoelectric resonator; and a second conductive layer between the substrate and the first conductive layer, the second conductive layer having an electric conductivity greater than that of the first conductive layer and an acoustic impedance different from that of the first conductive layer, wherein the first conductive layer and the second conductive layer extend from a first region that is between the first contact pad and the substrate to a second region that is between the piezoelectric resonator and the substrate, wherein the first conductive layer is tungsten and the second conductive layer is aluminum. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification