Magnetic switching element and a magnetic memory

• US 20030151944A1
• Filed: 12/27/2002
• Published: 08/14/2003
• Est. Priority Date: 12/27/2001
• Status: Active Grant

• Current Assignee: Kioxia Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Saito, Yoshiaki
• Granted Patent: US 6,807,091 B2
• Time in Patent Office: Days
• US Class Current: 365/173
• CPC Class Codes: G11C 11/15 using multiple magnetic layers G11C11/155 takes precedence
• CPC Class Codes: G11C 11/16 using elements in which the storage effect is based on magnetic spin effect
• 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 11/1675 Writing or programming circuits or methods
• CPC Class Codes: G11C 11/18 using Hall-effect devices
• CPC Class Codes: G11C 2213/74 Array wherein each memory cell has more than one access device
• CPC Class Codes: G11C 2213/75 Array having a NAND structure comprising, for example, memory cells in series or memory elements in series, a memory element being a memory cell in parallel with an access transistor
• CPC Class Codes: H10B 61/10 comprising components having two electrodes, e.g. diodes or MIM elements
• CPC Class Codes: H10B 61/22 of the field-effect transistor [FET] type
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A magnetic switching element includes: a ferromagnetic layer which is substantially pinned in magnetization in one direction; and a magnetic semiconductor layer provided within a range where a magnetic field from the ferromagnetic layer reaches, where the magnetic semiconductor layer changes its state from a paramagnetic state to a ferromagnetic state by applying a voltage thereto, and a magnetization corresponding to the magnetization of the ferromagnetic layer is induced in the magnetic semiconductor layer by applying a voltage to the magnetic semiconductor layer.

Claims

1. A magnetic switching element comprising:

a ferromagnetic layer which is substantially pinned in magnetization in one direction; and

a magnetic semiconductor layer provided within a range where a magnetic field from the ferromagnetic layer reaches, the magnetic semiconductor layer changing its state from a paramagnetic state to a ferromagnetic state by applying a voltage thereto,

a magnetization corresponding to the magnetization of the ferromagnetic layer being induced in the magnetic semiconductor layer by applying a voltage to the magnetic semiconductor layer.

2. A magnetic switching element according to claim 1, further comprising an anti-ferromagnetic layer provided to adjoin the ferromagnetic layer.

3. A magnetic switching element according to claim 1, further comprising a layered structure provided to adjoin the ferromagnetic layer, the layered structure including a nonmagnetic layer, a ferromagnetic film and an anti-ferromagnetic layer stacked in this order, and a direction of the magnetization of the ferromagnetic layer and a direction of a magnetization of the ferromagnetic film being opposite.

4. A magnetic switching element comprising:

a gate electrode;

a magnetic semiconductor layer which changes its state from a paramagnetic state to a ferromagnetic state by applying a voltage thereto; and

a ferromagnetic layer provided between the gate electrode and the magnetic semiconductor layer or provided on a opposite side of the magnetic semiconductor layer from the gate electrode, the ferromagnetic layer being substantially pinned in magnetization in one direction,

a magnetization corresponding to the magnetization of the ferromagnetic layer being induced in the magnetic semiconductor layer by applying a voltage to the magnetic semiconductor layer through the gate electrode.

5. A magnetic switching element according to claim 4, further comprising a gate insulating layer provided between the gate electrode and the magnetic semiconductor layer.

6. A magnetic switching element according to claim 4, wherein the ferromagnetic layer is provided between the gate electrode and the magnetic semiconductor layer and the ferromagnetic layer is electrically insulative.

7. A magnetic switching element according to claim 4, further comprising an anti-ferromagnetic layer provided to adjoin the ferromagnetic layer.

8. A magnetic switching element according to claim 4, further comprising a layered structure provided to adjoin the ferromagnetic layer, the layered structure including a nonmagnetic layer, a ferromagnetic film and an anti-ferromagnetic layer stacked in this order, and a direction of the magnetization of the ferromagnetic layer and a direction of a magnetization of the ferromagnetic film being opposite.

9. A magnetic memory comprising a memory cell having:

a first magnetic switching element including;

a first ferromagnetic layer which is substantially pinned in magnetization in a first direction; and

a first magnetic semiconductor layer provided within a range where a magnetic field from the first ferromagnetic layer reaches, the first magnetic semiconductor layer changing its state from a paramagnetic state to a ferromagnetic state by applying a voltage thereto,

a magnetization corresponding to the magnetization of the first ferromagnetic layer being induced in the first magnetic semiconductor layer by applying a voltage to the first magnetic semiconductor layer,

a second magnetic switching element including;

a second ferromagnetic layer which is substantially pinned in magnetization in a second direction; and

a second magnetic semiconductor layer provided within a range where a magnetic field from the second ferromagnetic layer reaches, the second magnetic semiconductor layer changing its state from a paramagnetic state to a ferromagnetic state by applying a voltage thereto,

a magnetization corresponding to the magnetization of the second ferromagnetic layer being induced in the second magnetic semiconductor layer by applying a voltage to the second magnetic semiconductor layer; and

a magnetoresistance effect element including a record layer made of a ferromagnetic material,

a magnetization corresponding to the magnetization of the first magnetic semiconductor layer being recorded in the record layer when the magnetization is induced in the first magnetic semiconductor layer of the first magnetic switching element, and

a magnetization corresponding to the magnetization of the second magnetic semiconductor layer being recorded in the record layer when the magnetization is induced in the second magnetic semiconductor layer of the second magnetic switching element.

10. A magnetic memory according to claim 9, wherein the magnetoresistance effect element further includes a pinned layer made of a ferromagnetic material and a tunnel barrier layer provided between the record layer and the pinned layer.

11. A magnetic memory according to claim 9, wherein the first direction and second direction are opposite.

12. A magnetic memory according to claim 11, wherein the record layer has an uniaxial anisotropy along which the magnetization occurs easily, and the uniaxis is substantially in parallel to the direction of the magnetization induced in the first and second magnetic semiconductor layers.

13. A magnetic memory comprising a memory cell having:

a first magnetic switching element including;

a first gate electrode;

a first magnetic semiconductor layer which changes its state from a paramagnetic state to a ferromagnetic state by applying a voltage thereto; and

a first ferromagnetic layer provided between the first gate electrode and the first magnetic semiconductor layer or provided on a opposite side of the first magnetic semiconductor layer from the first gate electrode, the first ferromagnetic layer being substantially pinned in magnetization in a first direction,

a magnetization corresponding to the magnetization of the first ferromagnetic layer being induced in the first magnetic semiconductor layer by applying a voltage to the first magnetic semiconductor layer through the first gate electrode;

a second magnetic switching element including;

a second gate electrode;

a second magnetic semiconductor layer which changes its state from a paramagnetic state to a ferromagnetic state by applying a voltage thereto; and

a second ferromagnetic layer provided between the second gate electrode and the second magnetic semiconductor layer or provided on a opposite side of the second magnetic semiconductor layer from the second gate electrode, the second ferromagnetic layer being substantially pinned in magnetization in a second direction,

a magnetization corresponding to the magnetization of the second ferromagnetic layer being induced in the second magnetic semiconductor layer by applying a voltage to the second magnetic semiconductor layer through the second gate electrode; and

a magnetoresistance effect element including a record layer made of a ferromagnetic material,

a magnetization corresponding to the magnetization of the first magnetic semiconductor layer being recorded in the record layer when the magnetization is induced in the first magnetic semiconductor layer of the first magnetic switching element, and

a magnetization corresponding to the magnetization of the second magnetic semiconductor layer being recorded in the record layer when the magnetization is induced in the second magnetic semiconductor layer of the second magnetic switching element.

14. A magnetic memory according to claim 13, further comprising:

a first gate insulating layer provided between the first gate electrode and the first magnetic semiconductor layer; and

a second gate insulating layer provided between the second gate electrode and the second magnetic semiconductor layer.

15. A magnetic memory according to claim 13, wherein:

the first ferromagnetic layer is provided between the first gate electrode and the first magnetic semiconductor layer and the first ferromagnetic layer is electrically insulative, and

the second ferromagnetic layer is provided between the second gate electrode and the second magnetic semiconductor layer and the second ferromagnetic layer is electrically insulative.

16. A magnetic memory according to claim 13, further comprising a first anti-ferromagnetic layer provided to adjoin the first ferromagnetic layer, and a second anti-ferromagnetic layer provided to adjoin the second ferromagnetic layer.

17. A magnetic memory according to claim 13, further comprising a layered structure provided to adjoin either one of the first and second ferromagnetic layers, the layered structure including a nonmagnetic layer, a ferromagnetic film and an anti-ferromagnetic layer stacked in this order, and a direction of the magnetization of the ferromagnetic layer and a direction of a magnetization of the ferromagnetic film being opposite.

18. A magnetic memory according to claim 13, wherein the magnetoresistance effect element further includes a pinned layer made of a ferromagnetic material and a tunnel barrier layer provided between the record layer and the pinned layer.

19. A magnetic memory according to claim 13, wherein the first direction and second direction are opposite.

20. A magnetic memory according to claim 19, wherein the record layer has an uniaxial anisotropy along which the magnetization occurs easily, and the uniaxis is substantially in parallel to the direction of the magnetization induced in the first and second magnetic semiconductor layers.

21. A magnetic memory comprising a plurality of memory cells in a matrix arrangement, each one of the memory cells having:

a first magnetic switching element including;

a first ferromagnetic layer which is substantially pinned in magnetization in a first direction; and

a first magnetic semiconductor layer provided within a range where a magnetic field from the first ferromagnetic layer reaches, the first magnetic semiconductor layer changing its state from a paramagnetic state to a ferromagnetic state by applying a voltage thereto,

a magnetization corresponding to the magnetization of the first ferromagnetic layer being induced in the first magnetic semiconductor layer by applying a voltage to the first magnetic semiconductor layer;

a second magnetic switching element including;

a second ferromagnetic layer which is substantially pinned in magnetization in a second direction; and

a second magnetic semiconductor layer provided within a range where a magnetic field from the second ferromagnetic layer reaches, the second magnetic semiconductor layer changing its state from a paramagnetic state to a ferromagnetic state by applying a voltage thereto,

a magnetization corresponding to the magnetization of the second ferromagnetic layer being induced in the second magnetic semiconductor layer by applying a voltage to the second magnetic semiconductor layer, and

a trimagnetoresistance effect element including a record layer made of a ferromagnetic material,

a magnetization corresponding to the magnetization of the first magnetic semiconductor layer being recorded in the record layer when the magnetization is induced in the first magnetic semiconductor layer of the first magnetic switching element, and

a magnetization corresponding to the magnetization of the second magnetic semiconductor layer being recorded in the record layer when the magnetization is induced in the second magnetic semiconductor layer of the second magnetic switching element,

binary information being recorded as the magnetization in the record layer of the magnetoresistance effect element of a predetermined one of the memory cells by selecting the memory cell and by applying the voltage to either one of the first and second magnetic semiconductor layers.