Method for controlling piezoelectric coupling coefficient in film bulk acoustic resonators and apparatus embodying the method
First Claim
1. An apparatus fabricated on a substrate, the apparatus comprising:
- a bottom electrode;
a composite layer on said bottom electrode, said composite layer comprising a piezoelectric layer having a first coupling coefficient said piezoelectric layer including Aluminum Nitride;
a coupling coefficient control layer having a second coupling coefficient, said coupling coefficient control layer including Aluminum Oxy-Nitride; and
a top electrode above said composite layer.
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Accused Products
Abstract
An apparatus such as a thin film resonator has a bottom electrode, a top electrode, and a composite layer between the two electrodes. The composite layer includes a piezoelectric (PZ) layer having a first coupling coefficient and a coupling coefficient control (CCC) layer having a second coupling coefficient. By varying the relative thicknesses of the PZ layer and the CCC layer during the manufacturing process, the coupling coefficient of the resonator can be established (to any value between the first coupling coefficient and the second coupling coefficient) with minimal impact on resonant frequency. Further, it is relatively less difficult to fabricate the PZ layer and the CCC layer having the desired coupling coefficient (as a combination of the first coupling coefficient and the second coupling coefficient) compared to the difficulties of fabrication of a uniform PZ layer having the desired coupling coefficient.
100 Citations
12 Claims
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1. An apparatus fabricated on a substrate, the apparatus comprising:
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a bottom electrode;
a composite layer on said bottom electrode, said composite layer comprising a piezoelectric layer having a first coupling coefficient said piezoelectric layer including Aluminum Nitride;
a coupling coefficient control layer having a second coupling coefficient, said coupling coefficient control layer including Aluminum Oxy-Nitride; and
a top electrode above said composite layer. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of fabricating an apparatus, the method comprising:
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fabricating a bottom electrode on a substrate;
fabricating a composite layer on said bottom electrode, said composite layer comprising a piezoelectric layer having a first coupling coefficient said piezoelectric layer including Aluminum Nitride;
a coupling coefficient control layer having a second coupling coefficient, said coupling coefficient control layer including Aluminum Oxy-Nitride; and
fabricating a top electrode above said composite layer. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification