MICROELECTROMECHANICAL AND/OR NANOELECTROMECHANICAL STRUCTURE WITH A VARIABLE QUALITY FACTOR

• US 20140318906A1
• Filed: 04/24/2014
• Published: 10/30/2014
• Est. Priority Date: 04/25/2013
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: DEIMERLY, Yannick, JOURDAN, Guillaume, REY, Patrice
• Granted Patent: US 9,834,432 B2
• Time in Patent Office: Days
• US Class Current: 188/156
• CPC Class Codes: B81B 2201/025 Inertial sensors not provided for in B81B2201/0235 - B81B2201/0242
• CPC Class Codes: B81B 7/0016 Protection against shocks or vibrations, e.g. vibration damping
• CPC Class Codes: B81B 7/008 MEMS characterised by an electronic circuit specially adapted for controlling or driving the same B81B7/0087 takes precedence; arrangements for starting, regulating, braking, or otherwise controlling an actuator H02N; control arrangements or circuits for visual indicators G09G3/00
• CPC Class Codes: G01C 19/5726 Signal processing
• CPC Class Codes: G01P 2015/0882 for providing damping of vibrations
• CPC Class Codes: Y10T 29/49082 Resistor making

Abstract

Inertial sensor comprising a fixed part and at least one mass suspended from the fixed part and means of damping the displacement of the part suspended from the fixed part, said damping means being electromechanical damping means comprising at least one DC power supply source, one electrical resistor and one variable capacitor in series, said variable capacitor being formed partly by the suspended part and partly by the fixed part such that displacement of the suspended part causes a variation of the capacitance of the variable capacitor.

Claims

1. A microelectromechanical and/or nanoelectromechanical structure comprising at least one fixed part and at least one part suspended from the fixed part and means of damping the displacement of the part suspended from the fixed part, said damping means being electromechanical damping means comprising at least one DC power supply source, at least n assemblies comprising an electrical resistor and a variable capacitor or a subassembly of variable capacitors connected in parallel, in series with the resistor, said n assemblies being connected in parallel on the DC power supply source, so as to form n loops with the same power supply source or each assembly being connected to a DC power supply source, each variable capacitor being formed partly by the suspended part and partly by the fixed part such that displacement of the suspended part causes a variation of the capacitance of said variable capacitor.

2. The structure according to claim 1, in which the resistors of at least two assemblies are the same.

3. The structure according to claim 1, in which n is an even number and the structure comprises a fixed part with n electrically independent patterns, the n variable capacitors in the n assemblies being formed by said n patterns in the fixed part, which are arranged on each side of the suspended part relative to a plane of symmetry of said suspended part.

4. The structure according to claim 1, in which the inertial mass comprises a comb with n teeth, and the fixed part comprises a comb with n teeth forming n patterns, the two combs being interdigitised such that one tooth of one comb and one tooth of another comb together form a variable capacitor.

5. The structure according to claim 1, in which the at least one variable capacitor is a variable air gap capacitor.

6. The structure according to claim 1, in which the at least one variable capacitor is a variable area capacitor.

7. The structure according to claim 1, in which at least one electrode of the at least one variable capacitor is formed by at least one test electrode of the structure.

8. The structure according to claim 1, in which the electrical resistor is partly formed by the fixed part.

9. The structure according to claim 1, in which the damping means are controllable so as to apply a variable damping force.

10. The structure according to claim 1, comprising means of detecting displacements of the suspended part and forming an inertial sensor.

11. The structure according to claim 10, in which the inertial sensor is an accelerometer.

12. The structure according to claim 10, comprising means of exciting at least part of the suspended part.

13. The structure according to claim 12, in which the damping means are controllable so as to apply a variable damping force, and in which the inertial sensor is a gyroscope.

14. An assembly comprising at least two inertial sensors integrated onto a single substrate, at least one of the two inertial sensors is an inertial sensor according to claim 10.

15. The assembly according to claim 14, comprising a gyroscope and an accelerometer, said gyroscope and said accelerometer being encapsulated in a cavity, the damping means being such that the accelerometer has a low quality factor.

16. A process for making a structure or an assembly according to claim 1 comprising the following steps:

making at least one electrical resistor of the damping means on or in a substrate that will at least partly form the fixed part,

making the suspended part and the fixed part of the structure, and

releasing at least the suspended part.

17. A production process according to claim 16, in which the step to make said at least electrical resistor comprises a doping step so as to control the electrical resistivity of the part of the material in which the resistor is made.

18. The production process according to claim 16, comprising a step to form a protective layer on said electrical resistor before production of the suspended part and the fixed part of the structure.