Three axis magnetic sensor device and method

• US 8,742,520 B2
• Filed: 06/21/2013
• Issued: 06/03/2014
• Est. Priority Date: 08/19/2010
• Status: Active Grant

• Current Assignee: Movella Incorporated (Movella Holdings, Inc.)
• Original Assignee: mCube, Inc.
• Inventors: Wan, Hong, Yang, Xiao (Charles)
• Primary Examiner(s): Valentine, Jami M
• Application Number:
  US13/924,457
• Publication Number:
  US 20130285651A1
• Time in Patent Office: 347 Days
• Field of Search: 257421-427, 257/E29.323, 438/3, 365157-158, 365171-173, 360324-326
• US Class Current: 257/421
• 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 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: H10B 61/00 Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 59/00 Integrated devices, or assemblies of multiple devices, comprising at least one galvanomagnetic or Hall-effect element covered by groups H10N50/00 - H10N52/00 MRAM devices H10B61/00

Abstract

A method and structure for a three-axis magnetic field sensing device is provided. The device includes a substrate, an IC layer, and preferably three magnetic field sensors coupled to the IC layer. A nickel-iron magnetic field concentrator is also provided.

Claims

1. A device for sensing magnetic fields, the device comprising:

a substrate member having a surface region;

an integrated circuit (IC) layer spatially disposed overlying at least a portion of the surface region;

a first magnetic field sensor element including at least a first material and configured to detect at least in a first direction, the first magnetic field sensor element being operably coupled to the IC layer;

a second magnetic field sensor element including at least the first material and configured to detect at least in a second direction, the second magnetic field sensing element being operably coupled to the IC layer;

a third magnetic field sensor element including at least the first material and configured to detect at least in a third direction, the third magnetic sensing element being operably coupled to the IC layer; and

at least one magnetic field concentrator spatially formed overlying at least one portion of the surface region;

wherein all of the first, second and third directions are configured in a mutually orthogonal manner.

2. The device of claim 1 wherein the substrate member comprises a silicon material, a dielectric material, or a polymer.

3. The device of claim 1 wherein the substrate member has at least one portion patterned through a wet etching, dry etching, deep reactive-ion etching (DRIE), or mechanical process.

4. The device of claim 1 wherein the IC layer comprises a silicon material, a dielectric material, or a metal material.

5. The device of claim 1 wherein the IC layer comprises at least one IC device.

6. The device of claim 1 wherein the first, second, and third magnetic field sensor elements comprise ordinary magneto-resistive (OMR) devices, anisotropic magneto-resistive (AMR) devices, giant magneto-resistive (GMR) devices, or tunnel junction magneto-resistive (TMR) devices.

7. The device of claim 1 wherein the first, second, and third magnetic field sensor elements comprise thin film device(s), the thin film device(s) being deposited overlying at least one portion of the surface region.

8. The device of claim 1 wherein the first, second, and third magnetic field sensor elements are formed as a Wheatstone bridges, half bridges, or single elements.

9. The device of claim 1 wherein the first magnetic field sensor element is configured to be 45 degrees away from a crystal easy axis direction.

10. The device of claim 1 wherein the first magnetic sensor element is configured to detect magnetic fields in the x-axis direction.

11. The device of claim 1 wherein the second magnetic field sensor element is configured to be −

45 degrees away from a crystal easy axis element.

12. The device of claim 1 wherein the second magnetic field sensor element is configured to detect magnetic fields in the y-axis direction.

13. The device of claim 1 wherein the first and second magnetic field sensor elements are configured to be symmetrical across a crystal hard axis.

14. The device of claim 1 wherein the third magnetic field sensor element is configured to a direction on a crystal hard axis or a crystal easy axis.

15. The device of claim 1 wherein the third magnetic field sensor element is aligned to the first or second magnetic sensor element.

16. The device of claim 1 wherein the third magnetic field sensor element is configured to detect magnetic fields in the z-axis direction, the third magnetic field sensor element being able to detect vertical magnetic fields via the field concentrator(s).

17. The device of claim 1 further comprising a conductive strap disposed within a vicinity of the first, second, and third magnetic field sensor elements.

18. The device of claim 17 wherein the conductive strap comprises a metal or metal alloy.

19. The device of claim 1 wherein the field concentrator(s) comprise a nickel-iron (NiFe) material or a nickel iron cobalt (NiFeCo) material.

20. The device of claim 1 wherein the field concentrator(s) comprise permalloy materials, the permalloy materials having high permeability.