Collector arrangement for magnetotransistor

• US 5,323,050 A
• Filed: 06/01/1993
• Issued: 06/21/1994
• Est. Priority Date: 06/01/1993
• Status: Expired due to Fees

• Current Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Ristic, Ljubisa
• Primary Examiner(s): MINTEL, WILLIAM A
• Application Number:
  US08/069,802
• Time in Patent Office: 385 Days
• Field of Search: 257/421, 257/422, 257/423, 257/424, 257/425, 257/426, 257/427, 257/414, 324/252
• US Class Current: 257/414
• CPC Class Codes: G01R 33/0088 use of bistable or switching devices, e.g. Reed-switches
• CPC Class Codes: G01R 33/06 using galvano-magnetic devices
• CPC Class Codes: G01R 33/066 field-effect magnetic sensors, e.g. magnetic transistor
• CPC Class Codes: H01L 29/82 controllable by variation of the magnetic field applied to the device

Abstract

A collector arrangement for a magnetotransistor (10, 25, 30) and a method for making the magnetotransistor (10, 25, 30). A portion of a semiconductor substrate (11) is doped to form a base region (13). The base region is doped to form an emitter region (16, 26, 36) and a collector region (17, 27, 37) such that the collector region (17, 27, 37) surrounds and is spaced apart from the emitter region (16, 26, 36). Collector contacts (C₁ -C₈ and C₅ '"'"'-C₈ '"'"', C₁₃ -C₁₆) are symmetrically formed in the collector region (17, 27, 37). In a three-dimensional magnetotransistor (10, 25) the collector contacts include split-collector contacts (C₅ -C₈ and C₅ '"'"'-C₈ '"'"').

Claims

1. A collector arrangement for a magnetotransistor, comprising:

a semiconductor substrate of a first conductivity type, the semiconductor substrate having a principal surface;

a base region of a second conductivity type, the base region extending from the principal surface into the semiconductor substrate;

an emitter region of the first conductivity type, wherein the emitter region is within the base region and extends from the principal surface into the base region;

a collector region of the first conductivity type, wherein the collector region is an annularly shaped region that laterally surrounds and is spaced apart from the emitter region and extends from the principal surface into the base region;

a base contact, the base contact formed on the principal surface in the base region;

an emitter contact, the emitter contact formed on the principal surface of the emitter region; and

at least four collector contacts, each collector contact formed on the principal surface in the collector region, wherein a first and a second of the at least four collector contacts are adjacent opposite sides of the emitter region, and a third and a fourth of the at least four collector contacts are adjacent opposite sides of the emitter region.

2. A collector arrangement for a magnetotransistor as claimed in claim 1, wherein a plurality of injection suppression regions extend into the emitter region and form a plurality of conduction channels through which charge carriers flow.

3. A collector arrangement for a magnetotransistor as claimed in claim 1, wherein the base region includes a base contact region of the second conductivity type extending from the principal surface into the base region, the base contact region being an annularly shaped region that is spaced apart from and laterally surrounds the collector region.

4. A collector arrangement for a magnetotransistor as claimed in claim 2, wherein the emitter region is shaped in the form of a polygon having at least four sides which intersect to form at least four corners and each of the at least four corners has one of the plurality of injection suppression regions extending therefrom.

5. A collector arrangement for a magnetotransistor as claimed in claim 2, wherein the emitter region is shaped in the form of an octagon having eight sides and eight corners, each of the eight corners having one of the plurality of injection suppression regions extending therefrom, and the at least four collector contacts including at least two sets of two split-collector contacts, wherein a first and a second set of split-collector contacts are adjacent yet another set of laterally opposing sides of the emitter region.

6. A collector arrangement for a magnetotransistor as claimed in claim 1, wherein the at least four collector contacts include a set of split-collector contacts adjacent every other side of the emitter region.

7. A collector arrangement for a magnetotransistor as claimed in claim 5, wherein a first element from one set of two split-collector contacts is connected to a first element of another set of two split-collector contacts by a first conductive material and a second element from the one set of two split-collector contacts is connected to a second element of the another set of two split-collector contacts by a second conductive material.

8. A collector arrangement for a magnetotransistor as claimed in claim 1, wherein the emitter region is circular in shape.

9. A device for sensing a directional component of a magnetic flux density, comprising:

a transistor, the transistor having a base region, an emitter region, and a collector region, wherein the emitter and the collector regions are formed within the base region such that the collector region is an annular shaped region spaced apart from and surrounding the emitter region;

a base contact which contacts the base region;

an emitter contact which contacts the emitter region; and

a plurality of collector contacts which contact the collector region, wherein a first and a second of the plurality of collector contacts are adjacent opposite sides of the emitter region and a third and a fourth of the plurality of collector contacts are adjacent opposite sides of the emitter region such that a collector current in the first collector contact and a collector current in the second collector contact become imbalanced due to a first directional component of a magnetic flux density, and a collector current in the third collector contact and a collector current in the fourth collector contact become imbalanced due to a second directional component of the magnetic flux density when the device is placed in a magnetic field.

10. A device for sensing a directional component of a magnetic flux density as claimed in claim 9, further comprising:

a plurality of injection suppression regions, wherein the plurality of injection suppression regions extend into the emitter region; and

a base contact region, wherein the base contact region has an annular shape and is spaced apart from and surrounds the collector region.

11. A device for sensing a directional component of a magnetic flux density as claimed in claim 10, wherein the emitter region, the collector region, and the base contact region are rectangularly shaped, and the emitter region has four corners, each corner having one of the plurality of injection suppression regions extending therefrom.

12. A device for sensing a directional component of a magnetic flux density as claimed in claim 9, wherein the emitter and the collector regions are octagonally shaped, and the plurality of collector contacts include a fifth and a sixth collector contact that form a first set of split-collector contacts, and a seventh and an eighth collector contact that form a second set of split-collector contacts, wherein the first and the second sets of split-collector contacts are on opposite sides of the emitter region and a collector current within each set of split-collector contacts becomes imbalanced due to a third directional component of the magnetic flux density when the device is placed in a magnetic field.

13. A device for sensing a directional component of a magnetic flux density as claimed in claim 10, wherein the emitter and the collector regions are octagonally shaped, and the collector region has at least four sets of split-collector contacts wherein a first set and a second set of the at least four sets of split-collector contacts are on opposite sides of the emitter region and a third set and a fourth set of the at least four sets of split-collector contacts are on opposite sides of the emitter region.

14. A device for sensing a directional component of a magnetic flux density as claimed in claim 13, wherein one element of each set of the at least four sets of split-collector contacts are electrically connected and another element of each set of the at least four sets of split-collector contacts are electrically connected.

15. A device for sensing a directional component of a magnetic flux density as claimed in claim 13, wherein each set of the at least four sets of split-collector contacts comprises two collector contacts such that the collector current within each set of split-collector contacts becomes imbalanced due to a third directional component of the magnetic flux density when the device is placed in a magnetic field.

16. A device for sensing a directional component of a magnetic flux density as claimed in claim 10, wherein the plurality of injection suppression regions directs charge carriers towards the plurality of collector contacts.