MEMS sensor with a thin region
A piezoelectric microelectromechanical systems microphone is provided comprising a sensor, an anchor region at which the sensor is supported by a substrate, a first region of the sensor adjacent to the anchor region, the first region having at least one piezoelectric layer and at least one electrode, and a second region of the sensor, the second region being adjacent to the first region, having at least one piezoelectric layer and at least one electrode, and having a thickness less than the thickness of the first region. A method for manufacturing a piezoelectric microelectromechanical systems microphone is also provided.
1 . A piezoelectric microelectromechanical systems microphone comprising:
a sensor;
an anchor region at which the sensor is supported by a substrate;
a first region of the sensor adjacent to the anchor region, the first region having at least one piezoelectric layer and at least one electrode;
a second region of the sensor, the second region being adjacent to the first region, having at least one piezoelectric layer and at least one electrode, and having a thickness less than the thickness of the first region, at least one of an upper surface of the sensor or a lower surface of the sensor having a vertical step at a point of connection between the first region of the sensor and the second region of the sensor; and
a third region of the sensor, having at least one layer of material, wherein the third region is adjacent to the second region but not adjacent to the first region.
2 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the at least one piezoelectric layer of the second region of the sensor has thickness less than the thickness of the at least one piezoelectric layer of the first region of the sensor.
3 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the at least one electrode of the second region of the sensor has a thickness less than the thickness of the at least one piezoelectric layer of the first region of the sensor, and a single piezoelectric layer forms the at least one piezoelectric layer of the first region and the at least one piezoelectric layer of the second region.
4 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the at least one layer of material is a piezoelectric material.
5 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the at least one layer of material is a metal.
6 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the at least one layer of material is a low density material.
7 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the third region has a thickness equal to the thickness of the second region.
8 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the third region has a thickness different from the thickness of the second region.
9 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the third region comprises at least one corrugation.
10 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the second region comprises two piezoelectric layers and three electrode layers, where one of the electrode layers is a middle electrode located between the two piezoelectric layers, the first region comprises two piezoelectric layers and three electrode layers, where one of the electrode layers is a middle electrode located between the two piezoelectric layers, and the middle electrode of the first region and the middle electrode of the second region are the same electrode layer.
11 . The piezoelectric microelectromechanical systems microphone of claim 10 wherein the first region comprises four electrodes, two piezoelectric layers and at least one layer of non-piezoelectric material, one of the electrode layers of the first region is connected to an upper electrode of the second region, and another one of the electrode layers of the first region is connected to a lower electrode of the second region.
12 . The piezoelectric microelectromechanical systems microphone of claim 10 wherein the first region comprises five electrode layers and four piezoelectric layers, one of the electrode layers of the first region is connected to an upper electrode of the second region, and another one of the electrode layers of the first region is connected to a lower electrode of the second region.
13 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the at least one piezoelectric layer of the first region and/or the at least one piezoelectric layer of the second region is composed of aluminum nitride.
14 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the at least one electrode of the first region is composed of a different metal than the at least one electrode of the second region.
15 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the first region comprises three electrodes, two of which are connected in parallel.
16 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the sensor is a cantilever sensor.
17 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the sensor is a membrane sensor.
18 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein the first region of the sensor and the second region of the sensor define an active region of the sensor, and the third region of the sensor defines a passive region of the sensor.
19 . The piezoelectric microelectromechanical systems microphone of claim 1 wherein upper and lower surfaces of the sensor each have a vertical step at a point of connection between the second region of the sensor and the third region of the sensor.
20 . A wireless mobile device comprising:
one or more antennas;
a front end system that communicates with the one or more antennas; and
one or more piezoelectric microelectromechanical systems microphones, each microphone including a sensor, an anchor region at which the sensor is supported by a substrate, a first region of the sensor adjacent to the anchor region, the first region having at least one piezoelectric layer and at least one electrode, and a second region of the sensor, the second region being adjacent to the first region, having at least one piezoelectric layer and at least one electrode, and having a thickness less than the thickness of the first region, upper and lower surfaces of the sensor each having a vertical step at a point of connection between the first region of the sensor and the second region of the sensor.