Micromechanical component having a diaphragm

Patent metadata

Field	Value
Publication number	US-9850120-B2
Application number	US-201313761558-A
Country	US
Kind code	B2
Filing date	Feb 7, 2013
Priority date	Feb 10, 2012
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Measures are described with the aid of which not only a rupture, but also cracks may be detected in the diaphragm structure of a micromechanical component with the aid of circuit means integrated into the diaphragm structure. At least some circuit elements are integrated for this purpose into the bottom side of the diaphragm, i.e., into a diaphragm area directly adjoining the cavern below the diaphragm.

First claim

What is claimed is:

1. A micromechanical component, comprising:
at least one diaphragm which extends entirely across a cavern in the component, the component having a layered structure, wherein the diaphragm includes a top side and a bottom side, and wherein the cavern faces the bottom side; and
a plurality of connecting contacts inside the diaphragm, the connecting contacts including at least one pair of connecting contacts separated by an area of the diaphragm extending across the cavern, such that a voltage applied to the pair of connecting contacts generates a current from a first one of the pair of connecting contacts, directly through the separating area, and into a second one of the pair of connecting contacts, wherein the current is indicative of a resistance of the diaphragm such that a change in the resistance caused by a crack extending from the bottom side towards the top side is reflected in the current;
wherein the component includes a layered structure having a semiconductor substrate, and an epitaxial layer on the semiconductor substrate,
wherein the diaphragm is implemented in the epitaxial layer,
wherein the connecting contacts are each implemented in the form of a doped semiconductor area which extend into the epitaxial layer, and wherein the doped area is electrically contacted via a metal contact on a component surface to energize the diaphragm,
wherein the connecting contacts are between and girded by an insulation doping in the epitaxial layer to electrically decouple the diaphragm from other areas of the component, and
wherein the connecting contacts have a same doping type as the epitaxial layer, the connecting contacts being doped more strongly than the epitaxial layer.

2. The component as recited in claim 1 , further comprising:
a monitor to monitor a flow of the current through a layer of the diaphragm.

3. The component as recited in claim 1 , wherein in the diaphragm layer directly adjoining the cavern, at least one resistor element is provided which extends at least across an entire length or width of the diaphragm and is contacted via the pair of connecting contacts.

4. The component as recited in claim 3 , wherein the resistor element extends across an entire surface of the diaphragm.

5. The component as recited in claim 3 , wherein the at least one pair of connecting contacts includes a first pair of connecting contacts and a second pair of connecting contacts, wherein each pair generates a current directly through the separating area via the resistor element, and wherein current flow between the first pair and current flow between the second pair are in two different directions.

6. The component as recited in claim 5 , wherein the two directions are orthogonal.

7. The component as recited in claim 6 , wherein the doped semiconductor areas extend across an entire thickness of the diaphragm.

8. The component as recited in claim 6 , wherein the diaphragm is implemented in an epitaxial layer on a semiconductor substrate, and the connecting contacts are implemented in the form of doped semiconductor areas which extend into a depth at only a fraction of a thickness of the diaphragm starting from the component surface.

9. The component as recited in claim 7 , wherein the at least one resistor element has a same doping type as the epitaxial layer, the resistor element being doped more strongly than the epitaxial layer.

10. The component as recited in claim 7 , wherein current flow between the first pair of connecting contacts and the second pair of connecting contacts is conducted through a layer of the diaphragm directly adjoining the cavern, wherein the resistor element carries the current directly through the separating area without substantial parasitic currents occurring above the resistor element.

11. The component as recited in claim 7 , wherein the connecting contacts have a different doping type than the epitaxial layer, so that the connecting contacts are electrically insulated by a p-n junction against adjoining semiconductor material.

12. The component as recited in claim 2 , wherein, in the diaphragm layer directly adjoining the cavern, at least one wired-in heat source and at least one wired-in temperature sensor are situated, using which heat flow within the diaphragm is monitored.

13. The component as recited in claim 12 , wherein one of a resistor, a diode, or a transistor is used as the heat source, and the temperature sensor is in the form of one of a resistor, a diode, or a transistor.

14. The component as recited in claim 1 , wherein the diaphragm is implemented in an epitaxial layer on a semiconductor substrate, wherein the diaphragm is used and doped as a transistor, wherein an area of an edge of the diaphragm includes an emitter area and a collector area of the transistor, and wherein a monitor is provided to monitor collector-emitter current of the transistor.

15. The component as recited in claim 1 , wherein current flow between the first pair of connecting contacts and the second pair of connecting contacts is conducted through a layer of the diaphragm directly adjoining the cavern, and wherein a parasitic current flow is substantially prevented in an upper area of the diaphragm by a circumferential insulation doping located between the first pair of connecting contacts and the second pair of connecting contacts.

16. The component as recited in claim 9 , wherein current flow between the first pair of connecting contacts and the second pair of connecting contacts is conducted through a layer of the diaphragm directly adjoining the cavern, wherein the resistor element carries the current directly through the separating area without substantial parasitic currents occurring above the resistor element.

17. The component as recited in claim 8 , wherein the connecting contacts have a same doping type as the epitaxial layer, the connecting contacts being doped significantly more strongly than the epitaxial layer.

18. The component as recited in claim 17 , wherein the at least one resistor element has a same doping type as the epitaxial layer, the resistor element being doped significantly more strongly than the epitaxial layer.

19. The component as recited in claim 1 , wherein the at least one pair of connecting contacts includes a first pair of connecting contacts and a second pair of connecting contacts, wherein the first pair of connecting contacts and the second pair of connecting contacts each generate current directly through respective separating areas of the diaphragm, and wherein current flow between the first pair of connecting contacts and current flow between the second pair of connecting contacts are in two different directions that are orthogonal.

Assignees

• Bosch Gmbh Robert

Inventors

• Schiller Uwe
• Senz Volkmar
• Franz Jochen
• Grutzeck Helmut
• Mitschke Michaela

Classifications

• G01L19/0672

  Leakage or rupture protection or detection · CPC title

• B81B3/0078 Primary

  Constitution or structural means for improving mechanical properties not provided for in B81B3/007 - B81B3/0075 · CPC title

• B81C1/00253

  Processes for integrating an electronic processing unit with a micromechanical structure not provided for in B81C1/0023 - B81C1/00246 · CPC title

• B81C2203/075

  the electronic processing unit being integrated into an element of the micromechanical structure · CPC title

• G01L9/0042 Primary

  Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms (details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively) · CPC title