MEASUREMENT SYSTEM INCLUDING A NETWORK OF NANOELECTROMECHANICAL SYSTEM RESONATORS

• US 20150300999A1
• Filed: 10/02/2013
• Published: 10/22/2015
• Est. Priority Date: 10/02/2012
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation), Apix Analytics
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation), Apix Analytics
• Inventors: Andreucci, Philippe, Colinet, Eric, Duraffourg, Laurent, Puget, Pierre, Barattin, Rgis
• Granted Patent: US 9,945,822 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01N 30/6095 Micromachined or nanomachined, e.g. micro- or nanosize
• CPC Class Codes: G01N 30/64 Electrical detectors
• CPC Class Codes: H03H 2009/02496 Horizontal, i.e. parallel to the substrate plane
• CPC Class Codes: H03H 9/02259 Driving or detection means
• CPC Class Codes: H03H 9/2457 Clamped-free beam resonators

Abstract

The invention relates to a measurement system including a network of nanoelectromechanical system (NEMS) resonators, characterized in that: each one of said resonators includes: an electrostatic activation device capable of generating a vibration of a beam exposed to said excitation signal, at least one piezoresistive stress gauge made of a doped semiconducting material, extending from the beam so as to detect a movement of said beam, the variation in the electrical resistance of said at least one gauge supplying an output signal; said network includes at least two groups of resonators, each group including at least two resonators having an identical empty resonance frequency, each group of resonators having an empty resonance frequency different from that of each other group; the resonators forming each group are connected in parallel; the groups of resonators forming said network are connected in parallel; said system includes a reading device designed to supply an excitation signal at the network input and to determine the resonance frequency of a group of resonators which is selected by injecting, into said excitation signal, a frequency component corresponding to the empty resonance frequency of each selected group of resonators, and by identifying, in the output signal of the network, a resonance frequency component of the selected group of resonators.

Claims

1. A measurement system comprising a network of nanoelectromechanical system (NEMS) resonators, wherein:

each of said resonators comprises;

an input for receiving an excitation signal and an output for supplying an output signal in response to said excitation signal, said output signal exhibiting resonance at the resonant frequency of the resonator,

a beam suspended with respect to a support, the natural resonant frequency of the resonator corresponding to the natural resonant frequency of said beam,

an electrostatic activation device capable of generating a vibration of said beam under the effect of said excitation signal,

at least one piezoresistive strain gauge made of doped semiconductor material, suspended with respect to said support and extending from the beam in such a way as to detect a displacement of said beam, the variation in electrical resistance of said at least one gauge supplying said output signal,

said network comprises at least two groups of resonators, each group comprising at least two resonators exhibiting an identical natural resonant frequency, each group of resonators exhibiting a different natural resonant frequency from that of each other group,

the system comprises a memory wherein an item of information relating to the natural resonant frequency of each resonator or group of resonators is stored,

the resonators forming each group are connected in parallel, each group comprising an input and an output respectively connected to the input and output of each of said resonators, the groups of resonators forming said network are connected in parallel, said network comprising an input and an output respectively connected to the input and the output of each of said groups of resonators, and

said system comprises a reading device designed to supply an excitation signal to the input of the network and to determine the resonant frequency of a selected group of resonators by injecting into said excitation signal a frequency component corresponding to the natural resonant frequency stored in the memory for each selected group of resonators and by identifying, in the output signal of the network, a frequency component at the resonant frequency of the selected group of resonators.

2. The system according to claim 1, further comprising a device for summing the output signals of each group of resonators of the network into a total output signal of the network, and wherein the reading device is designed to determine the resonant frequency of a group of resonators from said total output signal of the network.

3. The system according to claim 2, wherein said reading device comprises a phase-locked loop (PLL) designed to lock a frequency of the excitation signal onto the frequency of a resonance peak of the output signal of the network and to supply the locked frequency as the excitation resonant frequency.

4. The system according to claim 1, wherein each group of resonators is functionalized with a different chemical species.

5. The system according to claim 1, wherein the resonators of the network are arranged on one and the same support in such a way as to form rows and columns of resonators running parallel to one another, the beams of the resonators being parallel to one another.

6. The system according to claim 1, wherein the resonators of the network are arranged on one and the same support in such a way as to form rows and columns of resonators running parallel to one another, said resonators being further arranged in such a way that, on one and the same row parallel to the beams of the resonators, two adjacent resonators are symmetrical with respect to a plane parallel to a column.

7. The system according to claim 1, further comprising at least one fluid channel intended for the flow of a gas sample to be analyzed, said network of resonators being arranged in said fluid channel in such a way that the beams of said resonators are exposed to said sample.

8. The system according to claim 7, further comprising at least two networks of resonators in said fluid channel.

9. The system according to claim 7, further comprising at least one said reference resonator arranged outside the fluid channel and connected to the same reading device as the network arranged in the fluid channel, and a processing system configured to combine the output signal of said reference resonator with the output signals of the groups of resonators of the network.

10. The system according to claim 7, wherein the network comprises at least one said reference resonator configured to be less sensitive to the gas sample than the other groups of resonators, and the system comprises a processing system configured to combine the output signal of said reference resonator with the output signals of the groups of resonators of the network.

11. The system according to claim 1, further comprising a processing system configured to combine the output signals of each group of resonators of the network with a mean of said signals.

12. The system according to claim 7, further comprising a gas chromatography column containing said fluid channel.

13. The system according to claim 12, wherein the channel of said chromatography column comprises a plurality of resonator networks distributed regularly between the input and the output of said column.

14. The system according to claim 7, further comprising a gas chromatography column upstream of said fluid channel in the direction of flow of the gas sample.

15. A method for reading a system according to claim 1, comprising the steps consisting in:

selecting a group of resonators to be read, from among the groups of resonators of the network,

retrieving from the memory the natural resonance information of each selected group of resonators,

applying an excitation signal to the network comprising a frequency component corresponding to the natural resonant frequency of each selected group of resonators,

determining the resonant frequency of each selected group of resonators by identifying, in the output signal of the network, a resonant frequency component of each selected group of resonators.

16. The method according to claim 15, wherein the application of said excitation signal generates in the output signal a core frequency component corresponding to the resonance of each selected group of resonators, and the resonant frequency of each selected group of resonators is determined by extracting said frequency component from the output signal of the network.

17. A process of fabrication of a system according to claim 1, comprising the collective fabrication, on a support made of a semiconductor material, of the resonators forming said network by employing microelectronics techniques.

18. The process according to claim 17, further comprising the collective functionalization of the groups of resonators of said network by chemical vapour deposition (CVD) or physical vapour deposition (PVD) of different chemical species for each of said groups.