QUANTUM TUNNELLING SENSOR DEVICE AND METHOD

• US 20110043229A1
• Filed: 08/24/2007
• Published: 02/24/2011
• Est. Priority Date: 08/24/2007
• Status: Active Grant

• Current Assignee: Chemtron Research LLC (Intellectual Ventures LLC)
• Original Assignee: Quantum Precision Instruments Asia Private Limited
• Inventors: Slodowy, Peter, Michalewicz, Marek
• Granted Patent: US 8,544,324 B2
• Time in Patent Office: Days
• US Class Current: 324/693
• CPC Class Codes: G01P 15/0894 by non-contact electron transfer, i.e. electron tunneling
• CPC Class Codes: G01Q 20/04 Self-detecting probes, i.e. wherein the probe itself generates a signal representative of its position, e.g. piezoelectric gauge
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

A sensor device, method of fabricating the same, and a method of sensing a physical quantity. The sensor device comprises a substrate; a flexure member, one end of the flexure member being attached to the substrate, and a free end of the flexure member having an edge surface; a counter surface formed on the substrate such that the counter surface faces the edge surface of the flexure member and such that a separation distance between the counter surface and the edge surface remains substantially constant for movement of the edge surface as a result of flexure of the flexure member, each of the edge surface and the counter surface including one or more conductor layers disposed in a plane substantially perpendicular to a flexure direction of the flexure member; and means for applying an electrical potential difference between the conductors of the edge surface and the conductors of the counter surface for detecting a quantum tunnelling current therebetween.

Claims

1-14. -14. (canceled)

15. A sensor device comprising:

a substrate;

a flexure member, one end of the flexure member being attached to the substrate, and a free end of the flexure member having an edge surface;

a counter surface formed on the substrate such that the counter surface faces the edge surface of the flexure member and such that a separation distance between the counter surface and the edge surface remains substantially constant for movement of the edge surface as a result of flexure of the flexure member, each of the edge surface and the counter surface including one or more conductor layers disposed in a plane substantially perpendicular to a flexure direction of the flexure member; and

means for applying an electrical potential difference between the conductors of the edge surface and the conductors of the counter surface for detecting a quantum tunnelling current therebetween.

16. The device as claimed in claim 15, wherein the conductor layers of the edge surface and the counter surface extend through to respective edge portions of the substrate for applying the electrical potential.

17. The device as claimed in claim 15, wherein insulating layers are provided between the conductor layers of the edge surface, the counter surface, or both.

18. The device as claimed in claim 15, wherein the flexure direction is substantially perpendicular to the substrate.

19. The device as claimed in claim 15, wherein the flexure direction is substantially parallel to the substrate.

20. The device as claimed in claim 15, wherein the flexure member is formed across a recess formed in the substrate, and the counter surface is formed as part of a wall structure of the recess.

21. The device as claimed in claim 20, wherein the recess has an exposed longitudinal edge along at least one side of the substrate.

22. The device as claimed in claim 21, wherein one side of the flexure member is aligned with said exposed edge of the recess.

23. The device as claimed in claim 20, wherein the recess is laterally enclosed along all sides of the recess.

24. The device as claimed in claim 15, further comprising a tip formed on a surface of the flexure member.

25. The device as claimed in claim 15, wherein the flexure member and the counter surface are built up on a surface of the substrate, and wherein a frame portion of the substrate extends around at least one longitudinal side of the flexure member.

26. The device as claimed in claim 15, wherein the counter surface extends below, above, or both, of a quiescent level of the flexure member along the flexure direction.

27. A method of sensing a physical quantity, the method comprising the steps of:

providing a flexure member, one end of the flexure member being attached to a substrate, and a free end of the flexure member having an edge surface;

providing a counter surface formed on the substrate such that the counter surface faces the edge surface of the flexure member, each of the edge surface and the counter surface including one or more conductor layers disposed in a plane substantially perpendicular to a flexure direction of the flexure member;

applying an electrical potential difference between the conductors of the edge surface and the conductors of the counter surface for detecting a quantum tunnelling current therebetween;

flexing the flexure member such that a separation distance between the counter surface and the edge surface remains substantially constant for movement of the edge surface as a result of flexure of the flexure member;

detecting the tunnelling current for sensing the physical quantity; and

wherein movement of the flexure member or vibratory properties of the flexure member are coupled to the physical quantity.

28. A method of fabricating a sensor device, the method comprising the steps of:

providing a substrate;

forming a flexure member, one end of the flexure member being attached to the substrate, and a free end of the flexure member having an edge surface;

forming a counter surface on the substrate such that the counter surface faces the edge surface of the flexure member and such that a separation distance between the counter surface and the edge surface remains substantially constant for movement of the edge surface as a result of flexure of the flexure member, each of the edge surface and the counter surface including one or more conductor layers disposed in a plane substantially perpendicular to a flexure direction of the flexure member; and

forming means for applying an electrical potential difference between the conductors of the edge surface and the conductors of the counter surface for detecting a quantum tunnelling current therebetween.