MEMS microphone
A MEMS microphone includes a substrate ( 100 ), a supporting part ( 200 ), an upper polar plate ( 300 ) and a lower polar plate ( 400 ). The substrate ( 100 ) is provided with an opening ( 120 ) penetrating the middle thereof; the lower polar plate ( 400 ) straddles the opening ( 120 ); the supporting part ( 200 ) is fixed on the lower polar plate ( 400 ); the upper polar plate ( 300 ) is affixed to the supporting part ( 200 ); an accommodating cavity ( 500 ) is formed among the supporting part ( 200 ), the upper polar plate ( 300 ) and the lower polar plate ( 400 ); a recess ( 600 ) opposite to the accommodating cavity ( 500 ) is arranged in an intermediate region of at least one of the upper polar plate ( 300 ) and the lower polar plate ( 400 ), and insulation is achieved between the upper polar plate ( 300 ) and a lower polar plate ( 400 ).
1. A MEMS microphone, comprising:
a substrate defining an opening extending through a middle portion thereof;
a lower polar plate straddling on the opening;
a supporting portion fixed to the lower polar plate; and
an upper polar plate laminated to the supporting portion,
wherein the supporting portion, the upper polar plate, and the lower polar plate cooperatively form an accommodating cavity;
a central region of the upper polar plate is provided with a recess corresponding to the accommodating cavity;
the upper polar plate is insulated from the lower polar plate; and
the supporting portion comprises one supporting post independent from a main body of the supporting portion,
the supporting post is configured to support an upper electrode, the upper electrode is positioned on the upper polar plate, and the supporting post is aligned with the upper electrode as viewed in a direction perpendicular to a thickness direction of the substrate.
2. The MEMS microphone according to claim 1 , wherein the upper polar plate is a flexible diaphragm, the lower polar plate is a rigid diaphragm.
3. The MEMS microphone according to claim 1 , wherein the upper polar plate is a rigid diaphragm, the lower polar plate is a flexible diaphragm.
4. The MEMS microphone according to claim 1 , wherein the upper polar plate or the lower polar plate defines a plurality of acoustic holes.
5. The MEMS microphone according to claim 1 , wherein a shape of the recess is selected from one of circular and polygon.
6. The MEMS microphone according to claim 1 , wherein the upper polar plate and the lower polar plate comprise a conductive layer.
7. The MEMS microphone according to claim 1 , wherein the substrate is made of one selected from the group consisting of Ge, SiGe, SiC, SiO2, and Si3N4.
8. The MEMS microphone according to claim 1 , wherein the supporting portion contains a first insulating layer configured to insulate the upper polar plate from the lower polar plate.
9. The MEMS microphone according to claim 1 , wherein the supporting portion comprises one of annular structure and polygon frame structure.
10. The MEMS microphone according to claim 1 , further comprising an upper electrode and a lower electrode, wherein the upper electrode and the lower electrode are made of one selected from the group consisting of P-type silicon and N-type silicon, the upper electrode is electrically coupled to the upper polar plate, the lower electrode is electrically coupled to the lower polar plate.
11. The MEMS microphone according to claim 1 , wherein a central region of the lower polar plate is provided with a recess corresponding to the accommodating cavity.
12. The MEMS microphone according to claim 1 , wherein a gap is formed between the supporting post and the main body of the supporting portion to space the upper electrode from the main body of the supporting portion.
13. The MEMS microphone according to claim 1 , wherein the supporting portion defines an aperture to expose the lower polar plate for fabricating a lower electrode, and the lower electrode is positioned in the aperture of the supporting portion.
14. The MEMS microphone according to claim 1 , wherein the supporting portion has a square frame structure.