VERTICAL HALL EFFECT SENSOR WITH CURRENT FOCUS

• US 20100219810A1
• Filed: 03/02/2009
• Published: 09/02/2010
• Est. Priority Date: 03/02/2009
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Rocznik, Thomas, Lang, Christoph, Kavusi, Sam
• Granted Patent: US 8,114,684 B2
• Time in Patent Office: Days
• US Class Current: 324/207.200
• CPC Class Codes: G01R 33/07 Hall effect devices
• CPC Class Codes: G01R 33/077 Vertical Hall-effect devices
• CPC Class Codes: H10N 52/01 Manufacture or treatment
• CPC Class Codes: H10N 52/101 Semiconductor Hall-effect devices

Abstract

A complimentary metal oxide semiconductor (CMOS) sensor system in one embodiment includes a doped substrate, a doped central island extending downwardly within the doped substrate from an upper surface of the doped substrate, and a first doped outer island extending downwardly within the doped substrate from the upper surface of the doped substrate, the first outer island electrically isolated from the central island within an upper portion of the substrate, and electrically coupled to the central island within a lower portion of the substrate.

Claims

1. A complimentary metal oxide semiconductor (CMOS) sensor system, comprising:

a doped substrate;

a doped central island extending downwardly within the doped substrate from an upper surface of the doped substrate; and

a first doped outer island extending downwardly within the doped substrate from the upper surface of the doped substrate, the first outer island electrically isolated from the central island within an upper portion of the substrate, and electrically coupled to the central island within a lower portion of the substrate.

2. The sensor system of claim 1, further comprising:

a first doped contact within the central island;

a second doped contact within the central island; and

a Hall voltage measuring device connected to the first doped contact and the second doped contact.

3. The sensor system of claim 1, further comprising:

a second doped outer island extending downwardly within the doped substrate from the upper surface of the doped substrate, the second outer island electrically isolated from the first outer island and the central island within the upper portion of the substrate, and electrically coupled to the central island within the lower portion of the substrate.

4. The sensor system of claim 3, further comprising:

a buried doped well within the lower portion of the substrate, the buried doped well electrically coupling the first outer island, the second outer island, and the central island.

5. The sensor system of claim 3, further comprising:

a buried doped well within a mid portion of the substrate, the buried doped well electrically isolating each of the first outer island, the second outer island, and the central island from the other of the first outer island, the second outer island, and the central island.

6. The sensor system of claim 3, further comprising:

a third doped outer island extending downwardly within the doped substrate from the upper surface of the doped substrate, the third outer island electrically isolated from the first outer island, the second outer island, and the central island within the upper portion of the substrate, and electrically coupled to the central island within the lower portion of the substrate; and

a fourth doped outer island extending downwardly within the doped substrate from the upper surface of the doped substrate, the fourth outer island electrically isolated from the first outer island, the second outer island, the third outer island, and the central island within the upper portion of the substrate, and electrically coupled to the central island within the lower portion of the substrate.

7. The sensor system of claim 6, wherein:

the first outer island, the second outer island, and the central island define a first axis along the surface of the substrate;

the third outer island, the fourth outer island, and the central island define a second axis along the surface of the substrate; and

the first axis is substantially orthogonal to the second axis.

8. The sensor system of claim 7, further comprising:

a first doped contact on the first axis within the central island;

a second doped contact on the first axis and spaced apart from the first doped contact within the central island;

a first Hall voltage measuring device connected to the first doped contact and the second doped contact;

a third doped contact on the second axis within the central island;

a fourth doped contact on the second axis and spaced apart from the third doped contact within the central island; and

a second Hall voltage measuring device connected to the third doped contact and the fourth doped contact.

9. A method of forming a complimentary metal oxide semiconductor (CMOS) sensor system, comprising:

doping a substrate;

forming a doped central island extending downwardly within the doped substrate from an upper surface of the doped substrate; and

forming a first doped outer island extending downwardly within the doped substrate from the upper surface of the doped substrate, the first outer island electrically isolated from the central island within an upper portion of the substrate, and electrically coupled to the central island within a lower portion of the substrate.

10. The method of claim 9, further comprising:

forming a first doped contact within the central island;

forming a second doped contact within the central island; and

connecting a Hall voltage measuring device to the first doped contact and the second doped contact.

11. The method of claim 9, further comprising:

forming a second doped outer island extending downwardly within the doped substrate from the upper surface of the doped substrate, the second outer island electrically isolated from the first outer island and the central island within the upper portion of the substrate, and electrically coupled to the central island within the lower portion of the substrate.

12. The method of claim 11, further comprising:

forming a buried doped well within the lower portion of the substrate, the buried doped well electrically coupling the first outer island, the second outer island, and the central island.

13. The method of claim 11, further comprising:

forming a buried doped well within a mid portion of the substrate, the buried doped well electrically isolating each of the first outer island, the second outer island, and the central island from the other of the first outer island, the second outer island, and the central island.

14. The sensor system of claim 11, further comprising:

forming a third doped outer island extending downwardly within the doped substrate from the upper surface of the doped substrate, the third outer island electrically isolated from the first outer island, the second outer island, and the central island within the upper portion of the substrate, and electrically coupled to the central island within the lower portion of the substrate; and

forming a fourth doped outer island extending downwardly within the doped substrate from the upper surface of the doped substrate, the fourth outer island electrically isolated from the first outer island, the second outer island, the third outer island, and the central island within the upper portion of the substrate, and electrically coupled to the central island within the lower portion of the substrate.

15. The method of claim 14, wherein:

the first outer island, the second outer island, and the central island are formed along a first axis along the surface of the substrate;

the third outer island, the fourth outer island, and the central island are formed along a second axis along the surface of the substrate; and

the first axis is substantially orthogonal to the second axis.

16. The method of claim 15, further comprising:

forming a first doped contact on the first axis within the central island;

forming a second doped contact on the first axis and spaced apart from the first doped contact within the central island;

connecting a first Hall voltage measuring device to the first doped contact and the second doped contact;

forming a third doped contact on the second axis within the central island;

forming a fourth doped contact on the second axis and spaced apart from the third doped contact within the central island; and

connecting a second Hall voltage measuring device to the third doped contact and the fourth doped contact.

17. A Vertical Hall effect sensor system comprising:

a first doped island extending downwardly into a substrate;

a current supply contact doped into the first doped island;

a first sensor device contact doped into the first doped island adjacent a first side of the current supply contact and located on a first axis extending through the current supply contact;

a second sensor device contact doped into the first doped island at a location on the first axis adjacent a second side of the current supply contact;

a second doped island extending downwardly into the substrate and located on the first axis;

a first current return contact doped into the second doped island;

a first doped leg positioned between the first doped island and the second doped island, the first doped leg inhibiting electrical flow between the first doped island and the second doped island; and

a doped connector extending beneath the first doped leg and electrically coupling the first doped island and the second doped island.

18. The system of claim 17, further comprising:

a third doped island extending downwardly into the substrate and located on the first axis such that the first island is located between the second island and the third island;

a second current return contact doped into the third doped island; and

a second doped leg positioned between the first doped island and the third doped island, the second doped leg inhibiting electrical flow between the first doped island and the third doped island, wherein the doped connector extends beneath the second doped leg and electrically couples the first doped island and the third doped island.

19. The system of claim 18, further comprising:

a fourth doped island extending downwardly into the substrate and located on a second axis extending through the supply contact;

a third current return contact doped into the fourth doped island;

a third doped leg positioned between the first doped island and the fourth doped island, the third doped leg inhibiting electrical flow between the first doped island and the fourth doped island;

a fifth doped island extending downwardly into the substrate and located on the second axis such that the first island is located between the fourth island and the fifth island;

a fourth current return contact doped into the fifth doped island; and

a fourth doped leg positioned between the first doped island and the fifth doped island, the fourth doped leg inhibiting electrical flow between the first doped island and the fifth doped island, wherein the doped connector extends beneath the third doped leg and the fourth doped leg and electrically couples the first doped island, the fourth doped island, and the fifth doped island.

20. The system of claim 19, further comprising:

a third sensor device contact doped into the first doped island adjacent a third side of the current supply contact and located on the second axis;

a fourth sensor device contact doped into the first doped island at a location on the second axis adjacent a fourth side of the current supply contact;

a first Hall voltage measuring device connected to the first sensor device contact and the second sensor device contact; and

a second Hall voltage measuring device connected to the third sensor device contact and the fourth sensor device contact.