MEMS 2D AND 3D MAGNETIC FIELD SENSORS AND ASSOCIATED MANUFACTURING METHOD

• US 20100097059A1
• Filed: 10/20/2008
• Published: 04/22/2010
• Est. Priority Date: 10/20/2008
• Status: Active Grant

• Current Assignee: University of North Carolina At Charlotte (University of North Carolina System)
• Original Assignee: University of North Carolina At Charlotte (University of North Carolina System)
• Inventors: ESTRADA, Horacio V., Maksymiv, Yaroslav
• Granted Patent: US 8,159,219 B2
• Time in Patent Office: Days
• US Class Current: 324/251
• CPC Class Codes: G01R 33/0005 Geometrical arrangement of magnetic sensor elements; Apparatus combining different magnetic sensor types G01R33/0206 takes precedence
• CPC Class Codes: G01R 33/0206 Three-component magnetometers
• CPC Class Codes: G01R 33/0286 comprising microelectromechanical systems [MEMS] MEMS devices in general B81B
• CPC Class Codes: G01R 33/07 Hall effect devices
• CPC Class Codes: H10N 52/101 Semiconductor Hall-effect devices

Abstract

The disclosure provides Hall effect device configurations capable of measuring magnetic fields in two dimensions (2D) and three dimensions (3D) along with associated microelectromechanical system (MEMS) manufacturing methods. The present invention includes various geometric layout configurations for 2D and 3D Hall effect devices with multidimensional magnetic field sensing elements. Advantageously, the present invention can provide, simultaneously and independently, absolute measurement of each of the components (i.e., x-, y-, and z-components) of a magnetic field. Additionally, the geometric layout configurations enable the Hall effect devices to be constructed with MEMS fabrication techniques.

Claims

1. A MEMS-based Hall probe, comprising:

a conductive material comprising a plurality of sides;

a plurality of contacts disposed to the plurality of sides, wherein an electric current is applied to the plurality of contacts such that the electrical current flows through the conductive material; and

a plurality of terminal pairs disposed to the plurality of sides.

2. The MEMS-based Hall probe of claim 1, further comprising:

a plurality of voltage measuring devices, wherein each of the plurality of voltage measuring devices are coupled to each of the plurality of terminal pairs to measure a voltage, and wherein the voltage is proportional to a magnetic field strength.

3. The MEMS-based Hall probe of claim 1, wherein the plurality of sides comprise a first side, a second side, a third side, a fourth side, a fifth side, and a sixth side;

wherein the first side is adjacent to the second side, the second side is adjacent to the third side, the third side is adjacent to the fourth side, and the fourth side is adjacent to the first side;

wherein the fifth side is adjacent to each of the first side, the second side, the third side, and the fourth side, the sixth side is adjacent to each of the first side, the second side, the third side, and the fourth side, and the fifth side is spaced apart from the sixth side.

4. The MEMS-based Hall probe of claim 3, wherein the MEMS-based Hall probe is configured to measure a magnetic field strength in two dimensions;

wherein the electric current flows from a first contact of the plurality of contacts disposed on the fifth side to a second contact of the plurality of contacts disposed on the sixth side; and

wherein the plurality of terminals comprise a first terminal disposed on the first side, a second terminal disposed on the second side, a third terminal disposed on the third side, and a fourth terminal disposed on the fourth side.

5. The MEMS-based Hall probe of claim 3, wherein the MEMS-based Hall probe is configured to measure a magnetic field strength in three dimensions;

wherein the electric current flows from a first contact disposed on the fifth side to a second contact disposed on the sixth side; and

wherein the plurality of terminals comprise a first terminal disposed on the fifth side, a second terminal disposed on the fifth side, a third terminal disposed on the fifth side, a fourth terminal disposed on the sixth side, a fifth terminal disposed on the sixth side, and a sixth terminal disposed on the sixth side.

6. The MEMS-based Hall probe of claim 5, further comprising:

an x-component voltage measuring device connected to the first terminal and the fourth terminal;

a y-component voltage measuring device connected to the second terminal and the fifth terminal; and

a z-component voltage measuring device connected to the third terminal and the fifth terminal;

wherein each of the x-component voltage measuring device, the y-component voltage measuring device, and the z-component voltage measuring device are configured to independently and separately measure a voltage proportional to an interaction of the electric current with a magnetic field.

7. The MEMS-based Hall probe of claim 3, wherein the MEMS-based Hall probe is configured to measure a magnetic field strength in three dimensions;

wherein the plurality of contacts comprise a first contact, a second contact, a third contact, and a fourth contact, wherein the electric current flows from the first contact disposed on the fifth side to each of the second contact disposed on the fifth side, the third contact disposed on the sixth side, and the fourth contact disposed on the sixth side; and

wherein the plurality of terminals comprise a first terminal disposed on the fifth side, a second terminal disposed on the fifth side, and a third terminal disposed on the sixth side.

8. The MEMS-based Hall probe of claim 7, further comprising:

an x-component voltage measuring device connected to the first terminal and the second terminal;

a y-component voltage measuring device connected to the second terminal and the third terminal; and

a z-component voltage measuring device connected to the first terminal and the second terminal;

wherein each of the x-component voltage measuring device, the y-component voltage measuring device, and the z-component voltage measuring device are configured to independently and separately measure a voltage proportional to an interaction of the electric current with a magnetic field.

9. The MEMS-based Hall probe of claim 1, wherein the MEMS-based Hall probe is fabricated by depositing multiple layers of a semiconducting material, and wherein the plurality of terminals and the plurality of contacts are formed through micromachining of the multiple layers.

10. A MEMS-based Hall sensing device, comprising:

a plurality of one-dimensional Hall probes, wherein each of the plurality of one-dimensional Hall probes comprise;

a conductive material comprising an applied current flowing through the conductive material; and

a pair of terminals disposed to the conductive material configured to measure a voltage orthogonal to the applied current responsive to an interaction between a magnetic field and the applied current.

11. The MEMS-based Hall sensing device of claim 10, wherein one-dimensional Hall probe pairs of the plurality of one-dimensional Hall probes are spaced apart from one another;

wherein the each of the one-dimensional Hall probe pairs comprises the applied current flowing in opposing directions; and

wherein a combination of the voltage from each of the one-dimensional Hall probe pairs comprises a voltage measurement at a mid-point between the one-dimensional Hall probe pairs.

12. The MEMS-based Hall sensing device of claim 10, wherein the plurality of one-dimensional Hall probes comprise a first horizontal Hall probe, a second horizontal Hall probe, a first vertical Hall probe, a second vertical Hall probe, a third vertical Hall probe, and a fourth vertical Hall probe;

wherein the first horizontal Hall probe and the second horizontal Hall probe are spaced apart from one another, wherein the each of the first horizontal Hall probe and the second horizontal Hall probe comprises the applied current flowing in opposing directions; and

wherein a combination of the voltage from each of the first horizontal Hall probe and the second horizontal Hall probe comprises a voltage measurement at a mid-point between the first horizontal Hall probe and the second horizontal Hall probe;

wherein the first vertical Hall probe and the second vertical Hall probe are spaced apart from one another, wherein the each of the first vertical Hall probe and the second vertical Hall probe comprises the applied current flowing in opposing directions; and

wherein a combination of the voltage from each of the first vertical Hall probe and the second vertical Hall probe comprises a voltage measurement at a mid-point between the first vertical Hall probe and the second vertical Hall probe; and

wherein the third vertical Hall probe and the fourth vertical Hall probe are spaced apart from one another, wherein the each of the third vertical Hall probe and the fourth vertical Hall probe comprises the applied current flowing in opposing directions; and

wherein a combination of the voltage from each of the third vertical Hall probe and the fourth vertical Hall probe comprises a voltage measurement at a mid-point between the third vertical Hall probe and the fourth vertical Hall probe.

13. The MEMS-based Hall sensing device of claim 10, wherein the plurality of one-dimensional Hall probes comprise a first horizontal Hall probe, a second horizontal Hall probe, a third horizontal Hall probe, a fourth horizontal Hall probe, a first vertical Hall probe, and a second vertical Hall probe;

wherein the first horizontal Hall probe and the second horizontal Hall probe are spaced apart from one another, wherein the each of the first horizontal Hall probe and the second horizontal Hall probe comprises the applied current flowing in opposing directions; and

wherein a combination of the voltage from each of the first horizontal Hall probe and the second horizontal Hall probe comprises a voltage measurement at a mid-point between the first horizontal Hall probe and the second horizontal Hall probe;

wherein the third horizontal Hall probe and the fourth horizontal Hall probe are spaced apart from one another, wherein the each of the third horizontal Hall probe and the fourth horizontal Hall probe comprises the applied current flowing in opposing directions; and

wherein a combination of the voltage from each of the third horizontal Hall probe and the fourth horizontal Hall probe comprises a voltage measurement at a mid-point between the third horizontal Hall probe and the fourth horizontal Hall probe; and

wherein the first vertical Hall probe and the second vertical Hall probe are spaced apart from one another, wherein the each of the first vertical Hall probe and the second vertical Hall probe comprises the applied current flowing in opposing directions; and

wherein a combination of the voltage from each of the first vertical Hall probe and the second vertical Hall probe comprises a voltage measurement at a mid-point between the first vertical Hall probe and the second vertical Hall probe.

14. The MEMS-based Hall sensing device of claim 10, wherein the plurality of one-dimensional Hall probes comprise a first one-dimensional Hall probe and a second one dimensional Hall probe;

wherein the MEMS-based Hall sensing device further comprises a two-dimensional MEMS-based Hall probe comprising;

a conductive material comprising a first side, a second side, a third side, a fourth side, a fifth side, and a sixth side;

a plurality of contacts disposed to the conductive material, wherein an electric current is applied to the plurality of contacts such that the electrical current flows through the conductive material; and

a plurality of terminal pairs disposed to the conductive material.

wherein the first side is adjacent to the second side, the second side is adjacent to the third side, the third side is adjacent to the fourth side, and the fourth side is adjacent to the first side;

wherein the fifth side is adjacent to each of the first side, the second side, the third side, and the fourth side, the sixth side is adjacent to each of the first side, the second side, the third side, and the fourth side, and the fifth side is spaced apart from the sixth side.

wherein the electric current flows from a first contact of the plurality of contacts disposed on the fifth side to a second contact of the plurality of contacts disposed on the sixth side; and

wherein the plurality of terminals comprise a first terminal disposed on the first side, a second terminal disposed on the second side, a third terminal disposed on the third side, and a fourth terminal disposed on the fourth side; and

wherein the first one-dimensional Hall probe and the second one-dimensional Hall probe are spaced apart from one another, wherein the each of the first one-dimensional Hall probe and the second one-dimensional Hall probe comprises the applied current flowing in opposing directions; and

wherein a combination of the voltage from each of the first one-dimensional Hall probe and the second one-dimensional Hall probe comprises a voltage measurement at a mid-point between the first one-dimensional Hall probe and the second one-dimensional Hall probe; and

wherein the two-dimensional MEMS-based Hall probe is located between the first one-dimensional Hall probe and the second one-dimensional Hall probe.

15. The MEMS-based Hall sensing device of claim 10, wherein the plurality of one-dimensional Hall probes are fabricated utilizing chemical vapor deposition and patterning by on of chemical and reactive etching.

16. A method of manufacturing a MEMS-based Hall probe, comprising:

preparing a substrate wafer;

depositing a semiconducting material on the substrate wafer;

patterning a Hall probe out of the semiconducting material; and

forming a sensing element for the Hall probe.

17. The method of claim 16, further comprising:

adding connections for applying an electrical current and for measuring a voltage across the semiconducting material.

18. The method of claim 16, wherein the semiconducting material comprises one of a polysilicon material and a mono-crystalline material.

19. The method of claim 16, wherein the patterning comprises one of chemical and reactive etching.

20. The method of claim 16, wherein the depositing comprises chemical vapor deposition.