Joseph F Mcdowell

US Patent:

6388918, May 14, 2002

Filed:

Mar 14, 2000

Appl. No.:

09/525147

Inventors:

Joseph McDowell - Los Gatos CA 95030
James Harris - Saratoga CA 95070
Juan Monico - San Jose CA 95123
Otto Voegli - Morgan Hill CA 95037

International Classification:

G11C 1114

US Classification:

365171, 365173

Abstract:

The present invention, generally speaking, provides a magnetic memory element that is single domain in nature and has a geometry that mitigates the effects of half-select noise. In a preferred embodiment, the magnetic memory element takes the form of a magnetic post or tube having an aspect ratio in the range of 2:1 (more preferably 4:1). The outside diameter of the magnetic tube or post is preferably less than 0. 8 microns, more preferably 0. 6 microns or less. The magnetic post or tube then functions as a single magnetic domain. In the case of a magnetic tube, the skin of the tube is formed of a magnetic material and the interior of the tube is formed of a non-magnetic material. Suitable non-magnetic materials include copper, gold and silicon. The coercivity of the magnetic tube structure may be adjusted by adjusting the thickness of the magnetic skin. As a result, the magnetic memory element is readily scalable to smaller geometries as lithographic techniques improve.

US Patent:

6452239, Sep 17, 2002

Filed:

Mar 14, 2000

Appl. No.:

09/525453

Inventors:

Joseph McDowell - Los Gatos CA
James Harris - Saratoga CA
Juan Monico - San Jose CA
Otto Voegli - Morgan Hill CA

Assignee:

Plumeria Investments, Inc. - Los Altos CA

International Classification:

H01L 2982

US Classification:

257421, 257427

Abstract:

The present invention, generally speaking, provides a magnetic memory element that is single domain in nature and has a geometry that mitigates the effects of half-select noise. In a preferred embodiment, the magnetic memory element takes the form of a magnetic post or tube having an aspect ratio in the range of 2:1 (more preferably 4:1). The outside diameter of the magnetic tube or post is preferably less than 0. 8 microns, more preferably 0. 6 microns or less. The magnetic post or tube then functions as a single magnetic domain. In the case of a magnetic tube, the skin of the tube is formed of a magnetic material and the interior of the tube is formed of a non-magnetic material. Suitable non-magnetic materials include copper, gold and silicon. The coercivity of the magnetic tube structure may be adjusted by adjusting the thickness of the magnetic skin. As a result, the magnetic memory element is readily scalable to smaller geometries as lithographic techniques improve.

US Patent:

20020186584, Dec 12, 2002

Filed:

May 13, 2002

Appl. No.:

10/146468

Inventors:

Joseph McDowell - Los Gatos CA, US
James Harris - Menlo Park CA, US
Juan Monico - San Jose CA, US
Otto Voegli - Morgan Hill CA, US

International Classification:

G11C011/14

US Classification:

365/171000

Abstract:

The present invention, generally speaking, provides a magnetic memory element that is single domain in nature and has a geometry that mitigates the effects of half-select noise. In a preferred embodiment, the magnetic memory element takes the form of a magnetic post or tube having an aspect ratio in the range of 2:1 (more preferably 4:1). The outside diameter of the magnetic tube or post is preferably less than 0.8 microns, more preferably 0.6 microns or less. The magnetic post or tube then functions as a single magnetic domain. In the case of a magnetic tube, the skin of the tube is formed of a magnetic material and the interior of the tube is formed of a non-magnetic material. Suitable non-magnetic materials include copper, gold and silicon. The coercivity of the magnetic tube structure may be adjusted by adjusting the thickness of the magnetic skin. As a result, the magnetic memory element is readily scalable to smaller geometries as lithographic techniques improve. The combination of very small, single-domain size and a relatively large aspect ratio results in uniquely desirable properties. Current levels within any reasonable expectation operate to switch the state of the magnetic tube only when the magnetic tube is destabilized by running current through it. With current flowing through the magnetic tube, its state may be readily changed by running modest currents in opposite directions through two parallel conductors, one on each side of the magnetic tube. When the magnetic tube is switched, the single domain nature of the magnetic tube produces a signal that is typically 10-15 times stronger than signals produced by conventional magnetic memory elements. The magnetic tube functions as a vertical magnetic field generator and may be formed in intimate proximity to a magnetic field sensor such as above the gate of a magFET.

US Patent:

63262177, Dec 4, 2001

Filed:

Mar 14, 2000

Appl. No.:

9/525146

Inventors:

Joseph McDowell - Los Gatos CA
James Harris - Saratoga CA
Juan Monico - San Jose CA
Otto Voegli - Morgan Hill CA

Assignee:

Plumeria Investments, Inc. - Los Altos CA

International Classification:

H01L 21336

US Classification:

438 3

Abstract:

The present invention, generally speaking, provides a magnetic memory element that is single domain in nature and has a geometry that mitigates the effects of half-select noise. In a preferred embodiment, the magnetic memory element takes the form of a magnetic post or tube having an aspect ratio in the range of 2:1 (more preferably 4:1). The outside diameter of the magnetic tube or post is preferably less than 0. 8 microns, more preferably 0. 6 microns or less. The magnetic post or tube then functions as a single magnetic domain. In the case of a magnetic tube, the skin of the tube is formed of a magnetic material and the interior of the tube is formed of a non-magnetic material. Suitable non-magnetic materials include copper, gold and silicon. The coercivity of the magnetic tube structure may be adjusted by adjusting the thickness of the magnetic skin. As a result, the magnetic memory element is readily scalable to smaller geometries as lithographic techniques improve.

US Patent:

59264144, Jul 20, 1999

Filed:

Apr 4, 1997

Appl. No.:

8/833151

Inventors:

Joseph McDowell - Los Gatos CA
James Harris - Saratoga CA
Juan Monico - San Jose CA
Otto Voegli - Morgan Hill CA

Assignee:

Magnetic Semiconductors - Cupertino CA

International Classification:

G11C 1118

US Classification:

365170

Abstract:

Magnetic integrated circuit structures exhibit desirable characteristics for purposes of realizing a magnetic semiconductor memory. In combination with a carrier-deflection-type magnetic field sensor, each of a variety of magnet structures realize a condition in which the magnetic field is substantially orthogonal to the direction of travel of carriers of a sense current, thereby achieving maximum sensitivity. In general, the magnetic structures are highly efficient and achieve a high degree of control of the magnetic field. As a result, a minimum-size device such as a MOS device suffices for purposes of sourcing a magnetizing current. By basing a magnetic memory cell on a single minimum-size MOS device, a small cell may be realized that compares favorably with a conventional DRAM or FLASH memory cell. The greater degree of control over the magnetic field afforded by the magnetic structures enables cross-coupling between cells in a memory array to be minimized.

US Patent:

60514418, Apr 18, 2000

Filed:

May 12, 1998

Appl. No.:

9/083272

Inventors:

Joseph McDowell - Los Gatos CA
James Harris - Saratoga CA
Juan Monico - San Jose CA
Otto Voegli - Morgan Hill CA

Assignee:

Plumeria Investments, Inc. - Los Altos CA

International Classification:

H01L 2100
H01L 2982
H01L 4300
G11C 1115

US Classification:

438 3

Abstract:

The present invention, generally speaking, provides a magnetic memory element that is single domain in nature and has a geometry that mitigates the effects of half-select noise. In a preferred embodiment, the magnetic memory element takes the form of a magnetic post or tube having an aspect ratio in the range of 2:1 (more preferably 4:1). The outside diameter of the magnetic tube or post is preferably less than 0. 8 microns, more preferably 0. 6 microns or less. The magnetic post or tube then functions as a single magnetic domain. In the case of a magnetic tube, the skin of the tube is formed of a magnetic material and the interior of the tube is formed of a non-magnetic material. Suitable non-magnetic materials include copper, gold and silicon. The coercivity of the magnetic tube structure may be adjusted by adjusting the thickness of the magnetic skin. As a result, the magnetic memory element is readily scalable to smaller geometries as lithographic techniques improve.