Pressure sensor and method for operating a pressure sensor
A pressure sensor having a substrate, a counter-structure applied to the substrate, a dielectric on the counter-structure, a membrane on the dielectric, wherein the membrane or the counter-structure deflectable by a pressure applied, a protective structure, wherein the protective structure is isolated from the counter-structure or the membrane, wherein the protective structure is arranged with regard to the membrane or the counter-structure such that a capacity forms between the protective structure and the membrane or the protective structure and the counter-structure, and a provider for providing a potential at the protective structure differing from a potential at the counter-structure or the membrane.
1. A pressure sensor comprising:
a substrate;
a counter-structure applied to the substrate;
a dielectric on the counter-structure;
a membrane on the dielectric, wherein the membrane or the counter-structure is deflectable by a pressure applied;
a protective structure, the protective structure being isolated from the counter-structure and the membrane, the protective structure being arranged with regard to the membrane or the counter-structure such that a capacity forms between the protective structure and the membrane or the protective structure and the counter-structure; and
a provider for providing a potential at the protective structure differing from a potential at the counter-structure or the membrane.
2. The pressure sensor according to claim 1 , which is formed as a capacitor microphone.
3. The pressure sensor according to claim 1 , wherein the membrane or the counter-structure is in an area-overlapping relation to the protective structure.
4. The pressure sensor according to claim 1 , wherein the substrate comprises an electrically conducting region.
5. The pressure sensor according to claim 1 , wherein the electrically conducting region of the substrate forms a ground potential, wherein a potential of a protective structure, a potential of a membrane and a potential of a counter-structure are related to the ground potential.
6. The pressure sensor according to claim 1 , wherein the substrate is electrically isolated from the counter-structure and the membrane.
7. The pressure sensor according to claim 1 , wherein the membrane or the counter-structure includes an electrically conducting layer.
8. The pressure sensor according to claim 1 , wherein the protective structure in a multi-layered setup is arranged in a same level as the membrane or the counter-structure.
9. The pressure sensor according to claim 8 , wherein the recesses in the membrane or the counter-structure form lands and the protective structure overlaps the lands of the membrane or counter-structure not arranged in the same level.
10. The pressure sensor according to claim 8 , wherein the protective structure of the membrane or counter-structure arranged in the same level of the multi-layered setup is electrically isolated from the membrane or the counter-structure by a recess.
11. The pressure sensor according to claim 8 , wherein the multi-layered setup comprises a layer including the protective structure and the counter-structure or the protective structure and the membrane.
12. The pressure sensor according to claim 1 , wherein the protective structure at least partially surrounds the membrane or the counter-structure.
13. The pressure sensor according to claim 1 , wherein an electrical potential of a protective structure, in a state of rest, deviates less than 50% from the value of the potential of the counter-structure or the membrane.
14. The pressure sensor according to claim 1 , wherein the provider for providing a potential of a protective structure determines a potential at the counter-structure or the membrane and sets a potential at the protective structure depending on the value of the potential.
15. The pressure sensor according to claim 14 , wherein the provider for providing a potential at the protective structure sets the potential at the protective structure such that a potential value of the protective structure deviates less than 10% from the value of the potential at the membrane or the counter-structure.
16. The pressure sensor according to claim 15 , wherein the protective structure and the membrane or the counter-structure are separated galvanically.
17. The pressure sensor according to claim 14 , wherein the provider for providing a potential at the protective structure includes an impedance converter setting the potential on the protective structure via a voltage divider.
18. The pressure sensor according to claim 17 , wherein the impedance converter includes a transistor with a potential depending on a potential of the membrane or the counter-structure applied to an input of the transistor and a potential depending on the potential of the protective structure applied to a second input.
19. The pressure sensor according to claim 1 , wherein recesses in the membrane or the counter-structure form lands and an area of the protective structure overlaps the lands in the membrane or the counter-structure.
20. A method for operating a pressure sensor, comprising:
a substrate;
a counter-structure applied to the substrate;
a dielectric on the counter-structure;
a membrane on the dielectric, the membrane or the counter-structure being deflectable by a pressure applied; and
a protective structure arranged with regard to the membrane such that a capacity forms between the protective structure and the member or the protective structure and the counter-structure;
comprising a step of applying a potential to the protective structure differing from a potential of the counter-structure or the membrane.