Semiconductor element having a semi-magnetic contact

• US 6,963,096 B2
• Filed: 09/22/2003
• Issued: 11/08/2005
• Est. Priority Date: 03/20/2001
• Status: Expired due to Fees

• Current Assignee: Polaris Innovations Limited (Wi-LAN Inc.)
• Original Assignee: Infineon Technologies AG
• Inventors: Schmidt, Georg, Molenkamp, Laurens
• Primary Examiner(s): Huynh, Andy
• Application Number:
  US10/667,730
• Publication Number:
  US 20040113188A1
• Time in Patent Office: 778 Days
• Field of Search: 257/295, 257421-427
• US Class Current: 257/295
• CPC Class Codes: G01R 33/09 Magnetoresistive devices
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: G11C 11/1659 Cell access
• CPC Class Codes: G11C 11/1675 Writing or programming circuits or methods
• CPC Class Codes: H01L 29/66984 Devices using spin polarized carriers
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

The invention relates to a magnetoresistive semiconductor element, including a first contact and a second contact, and also a layer of a nonmagnetic semiconductor arranged between the first contact and the second contact. The first contact is composed of a semi-magnetic material. The semi-magnetic material is a strongly paramagnetic material whose electron spins have no preferential direction without an action of an external magnetic field. Under the action of an external magnetic field, the electrons are spin-polarized in the first contact. When a voltage is applied this results in the injection of spin-polarized electrons into the nonmagnetic semiconductor. As a result, in the nonmagnetic semiconductor, only one of the spin channels can be used for transporting the charge carriers, so that a positive magnetoresistive effect is obtained.

Claims

1. A magnetoresistive semiconductor element, comprising:

a first contact made of a semi-magnetic material;

a second contact;

a layer of a nonmagnetic semiconductor configured between said first contact and said second contact; and

a tunnel barrier configured between said first contact and said layer of said nonmagnetic semiconductor.

2. The magnetoresistive semiconductor element according to claim 1, wherein said semi-magnetic material is a semiconductor.

3. The magnetoresistive semiconductor element according to claim 1, wherein said second contact is made of a nonmagnetic material.

4. The magnetoresistive semiconductor element according to claim 1, wherein said second contact is made of a semi-magnetic material.

5. The magnetoresistive semiconductor element according to claim 4, further comprising a tunnel barrier configured between said second contact and said layer of said nonmagnetic semiconductor.

6. The magnetoresistive semiconductor element according to claim 1, wherein said second contact is made of a ferromagnetic material.

7. The magnetoresistive semiconductor element according to claim 6, further comprising a tunnel barrier configured between said second contact and said layer of said nonmagnetic semiconductor.

8. The magnetoresistive semiconductor element according to claim 1, wherein said semi-magnetic material is a II-IV semiconductor.

9. The magnetoresistive semiconductor element according to claim 8, wherein said II-VI semiconductor is Be_xMn_yZn_1-x-ySe with 0<

x<

1, 0<

y<

1 and 0.0001<

y<

0.2.

10. The magnetoresistive semiconductor element according to claim 1, further comprising a Schottky diode for providing a current path for decoupling.

11. The magnetoresistive semiconductor element according to claim 1, further comprising a pn diode for providing a current path for decoupling.

12. A storage element, comprising:

a magnetoresistive semiconductor element, containing;

a first contact made of a semi-magnetic material;

a second contact;

a layer of a nonmagnetic semiconductor configured between said first contact and said second contact; and

a tunnel barrier configured between said first contact and said layer of said nonmagnetic semiconductor; and

a ferromagnetic element configured adjacent said first contact.

13. The storage element according to claim 12, further comprising a Schottky diode for decoupling.

14. A field effect transistor, comprising:

a source electrode;

a drain electrode;

a gate electrode;

at least one first contact of a semi-magnetic material for injecting spin-polarized charge carriers into said source electrode and/or for extracting spin-polarized charge carriers from said drain electrode;

a tunnel barrier configured between said first contact and said source electrode; and

a tunnel barrier configured between said first contact and said drain electrode.

15. A bipolar transistor, comprising:

a section acting as an emitter;

a section acting as a collector;

a region configured between said emitter and said collector and acting as a base;

at least one first contact for injecting spin-polarized charge carriers into said emitter and/or for extracting spin-polarized charge carriers from said collector;

a tunnel barrier configured between said first contact and said emitter; and

a tunnel barrier configured between said first contact and said collector.

16. A magnetic sensor, comprising:

a magnetoresistive semiconductor element including;

a first

contact made of a semi-magnetic material, a second contact, a layer of a nonmagnetic semiconductor configured between said first contact and said second contact, and a tunnel barrier configured between said first contact and said layer of said nonmagnetic semiconductor;

a plurality of electric feed and discharge lines, each one of said plurality of electric feed and discharge lines connected to a respective one of said first contact and said second contact; and

a measuring device connected to said plurality of electric feed and discharge lines for measuring a change in electrical resistance.

17. A read head for reading information stored in magnetic storage media, comprising:

a magnetoresistive semiconductor element including;

a first contact made of a semi-magnetic material, a second contact, a layer of a nonmagnetic semiconductor configured between said first contact and said second contact, and a tunnel barrier configured between said first contact and said layer of said nonmagnetic semiconductor;

a plurality of electric feed and discharge lines, each one of said plurality of electric feed and discharge lines connected to a respective one of said first contact and said second contact; and

a measuring device connected to said plurality of electric feed and discharge lines for measuring a change in electrical resistance.