Resonator and electronic device
View Patent ↗The present application relates to a resonator and an electronic device. A high and low acoustic impedance alternating layer, a bottom temperature coefficient of frequency compensation layer, a bottom electrode layer, a piezoelectric layer, a top electrode layer and a top temperature coefficient of frequency compensation layer are sequentially stacked on a substrate by using a specific microfabrication process, to form a new resonator. The resonator can simultaneously show excellent characteristics of low loss, wide bandwidth, low temperature sensitivity and a small size through the special stack geometry, thereby having better operation reliability.
1 . A resonator, comprising:
a high and low acoustic impedance alternating layer arranged on a substrate;
a bottom temperature coefficient of frequency compensation layer arranged on a first surface of the high and low acoustic impedance alternating layer, a surface of the high and low acoustic impedance alternating layer in contact with the substrate being a second surface of the high and low acoustic impedance alternating layer, the first surface of the high and low acoustic impedance alternating layer being arranged opposite to the second surface of the high and low acoustic impedance alternating layer;
a bottom electrode layer arranged on a first surface of the bottom temperature coefficient of frequency compensation layer, a surface of the bottom temperature coefficient of frequency compensation layer in contact with the high and low acoustic impedance alternating layer being a second surface of the bottom temperature coefficient of frequency compensation layer, the first surface of the bottom temperature coefficient of frequency compensation layer being arranged opposite to the second surface of the bottom temperature coefficient of frequency compensation layer;
a piezoelectric layer arranged on a first surface of the bottom electrode layer, a surface of the bottom electrode layer in contact with the bottom temperature coefficient of frequency compensation layer being a second surface of the bottom electrode layer, the first surface of the bottom electrode layer being arranged opposite to the second surface of the bottom electrode layer;
a top electrode layer arranged on a first surface of the piezoelectric layer, a surface of the piezoelectric layer in contact with the bottom electrode layer being a second surface of the piezoelectric layer, the first surface of the piezoelectric layer being arranged opposite to the second surface of the piezoelectric layer;
a metal layer arranged on a first surface of the top electrode layer, wherein
a surface of the top electrode layer in contact with the piezoelectric layer being a second surface of the top electrode layer, and
the first surface of the top electrode layer being arranged opposite to the second surface of the top electrode layer; and
a top temperature coefficient of frequency compensation layer arranged on a first surface of the metal layer, wherein
a surface of the metal layer in contact with the top electrode layer is a second surface of the metal layer, and
the first surface of the metal layer is arranged opposite to the second surface of the metal layer, and
the metal layer is made of a different material as the top electrode layer to change resonant frequency of the resonator.
2 . The resonator according to claim 1 , wherein the high and low acoustic impedance alternating layer comprises a high acoustic impedance layer and a low acoustic impedance layer, acoustic impedance of the high acoustic impedance layer is higher than that of the low acoustic impedance layer, the high acoustic impedance layer and the low acoustic impedance layer are stacked alternately, a layer in contact with the substrate in the high and low acoustic impedance alternating layer is the low acoustic impedance layer, and a layer in contact with the bottom temperature coefficient of frequency compensation layer in the high and low acoustic impedance alternating layer is the high acoustic impedance layer.
3 . The resonator according to claim 2 , wherein thicknesses of the high acoustic impedance layer and the low acoustic impedance layer are not exactly same.
4 . The resonator according to claim 2 , wherein thicknesses of the high acoustic impedance layer and the low acoustic impedance layer are same.
5 . The resonator according to claim 1 , further comprising an additional layer, wherein the additional layer is arranged on a first surface of the top temperature coefficient of frequency compensation layer, a surface of the top temperature coefficient of frequency compensation layer in contact with the top electrode layer is a second surface of the top temperature coefficient of frequency compensation layer, and the first surface of the top temperature coefficient of frequency compensation layer is arranged opposite to the second surface of the top temperature coefficient of frequency compensation layer.
6 . The resonator according to claim 1 , wherein projections of the bottom electrode layer and the top electrode layer in a direction perpendicular to the substrate are all polygons.
7 . The resonator according to claim 1 , wherein the high and low acoustic impedance alternating layer, the bottom temperature coefficient of frequency compensation layer, the bottom electrode layer, the piezoelectric layer, the top electrode layer and the top temperature coefficient of frequency compensation layer have a same length in a same direction parallel to the substrate.
8 . The resonator according to claim 1 , wherein the high and low acoustic impedance alternating layer, the bottom temperature coefficient of frequency compensation layer, the bottom electrode layer, the piezoelectric layer, the top electrode layer and the top temperature coefficient of frequency compensation layer are not exactly the same in length in a same direction parallel to the substrate.
9 . The resonator according to claim 1 , wherein a total phase length of a top stack formed by the bottom temperature coefficient of frequency compensation layer, the bottom electrode layer, the piezoelectric layer, the top electrode layer and the top temperature coefficient of frequency compensation layer is greater than half a period of an excited vibration mode.
10 . The resonator according to claim 1 , wherein each of the bottom temperature coefficient of frequency compensation layer and the top temperature coefficient of frequency compensation layer has a temperature coefficient opposite to a temperature coefficient of the piezoelectric layer.
11 . The resonator according to claim 2 , wherein an acoustic thickness of each layer in the high and low acoustic impedance alternating layer is equal to one quarter of a period of an excited vibration mode.
12 . The resonator according to claim 5 , wherein the additional layer is a film layer formed by any one or any combination of Pt, Mo, Au, AlN, SiN, SiO 2 , Ti, W and Ru.
13 . An electronic device, comprising the resonator according to claim 1 .
14 . The resonator according to claim 2 , wherein
the high and low acoustic impedance alternating layer comprises a plurality of high acoustic impedance layers and a plurality of low acoustic impedance layers, and
the closer the high acoustic impedance layer is to the piezoelectric layer, the greater its thickness is, and the closer the low acoustic impedance layer is to the piezoelectric layer, the greater its thickness is.
15 . The resonator according to claim 1 , wherein the resonant frequency of the resonator is further changed by changing a thickness of the top temperature coefficient of frequency compensation layer.
16 . The resonator according to claim 5 , wherein the resonant frequency of the resonator is further changed by patterning the additional layer directly on top of the top temperature coefficient of frequency compensation layer.
17 . The resonator according to claim 1 , wherein the resonant frequency of the resonator is further changed by etching the top electrode layer.