Jing Zhang

US Patent:

7284316, Oct 23, 2007

Filed:

Nov 17, 2004

Appl. No.:

10/991712

Inventors:

Yiming Huai - Pleasanton CA, US
Jinqiu Zhang - Fremont CA, US
Jing Zhang - San Jose CA, US

Assignee:

Western Digital (Fremont), LLC - Lake Forest CA

International Classification:

G11B 5/127
H04R 31/00

US Classification:

2960316, 2960308, 2960313, 2960315, 2960318, 216 62, 216 65, 216 66, 36032411, 36032412, 427127, 427128, 451 5, 451 41

Abstract:

A method for forming a hard bias structure in a magnetoresistive sensor is disclosed. A magnetoresistive sensor having a soft magnetic bias layer, spacer layer, and a magnetoresistive layer, is formed over a substrate having a gap layer. A mask is formed over a portion of the magnetoresistive sensor structure to define a central region. The masked structure is ion milled to remove portions not shielded by the mask, to form the central region with sloped sides, and to expose a region of the gap layer laterally adjacent the sloped sides. A first underlayer is deposited onto at least the sloped sides at a high deposition angle. A second underlayer is deposited to at least partially overlap the first underlayer, and at a first lower deposition angle. A hard bias layer is deposited over at least a portion of the second underlayer, and at a second lower deposition angle.

US Patent:

20120063218, Mar 15, 2012

Filed:

Sep 2, 2011

Appl. No.:

13/225338

Inventors:

Yiming Huai - Pleasanton CA, US
Jing Zhang - Los Altos CA, US
Rajiv Yadav Ranjan - San Jose CA, US
Yuchen Zhou - San Jose CA, US
Roger Klas Malmhall - San Jose CA, US
Ioan Tudosa - Milpitas CA, US

Assignee:

Avalanche Technology, Inc. - Fremont CA

International Classification:

G11C 11/14
H01L 29/82

US Classification:

365171, 257421, 257E29323

Abstract:

A spin-torque transfer memory random access memory (STTMRAM) element includes a composite fixed layer formed on top of a substrate and a tunnel layer formed upon the fixed layer and a composite free layer formed upon the tunnel barrier layer, the magnetization direction of each of the composite free layer and fixed layer being substantially perpendicular to the plane of the substrate. The composite layers are made of multiple repeats of a bi-layer unit which consists of a non-magnetic insulating layer and magnetic layer with thicknesses adjusted in a range that makes the magnetization have a preferred direction perpendicular to film plane.

US Patent:

20120146167, Jun 14, 2012

Filed:

Oct 19, 2011

Appl. No.:

13/277187

Inventors:

Yiming Huai - Pleasanton CA, US
Yuchen Zhou - San Jose CA, US
Jing Zhang - Los Altos CA, US
Roger Klas Malmhall - San Jose CA, US
Ioan Tudosa - Milpitas CA, US
Rajiv Yadav Ranjan - San Jose CA, US

Assignee:

Avalanche Technology - Fremont CA

International Classification:

H01L 29/82
B05D 5/12

US Classification:

257421, 427130, 257E29323

Abstract:

A spin-torque transfer magnetic random access memory (STTMRAM) element employed to store a state based on the magnetic orientation of a free layer, the STTMRAM element is made of a first perpendicular free layer (PFL) including a first perpendicular enhancement layer (PEL). The first PFL is formed on top of a seed layer. The STTMRAM element further includes a barrier layer formed on top of the first PFL and a second perpendicular reference layer (PRL) that has a second PEL, the second PRL is formed on top of the barrier layer. The STTMRAM element further includes a capping layer that is formed on top of the second PRL.

US Patent:

20130119498, May 16, 2013

Filed:

Jan 9, 2013

Appl. No.:

13/737897

Inventors:

Yiming Huai - Pleasanton CA, US
Yuchen Zhou - San Jose CA, US
Jing Zhang - Los Altos CA, US
Roger Klas Malmhall - San Jose CA, US
Ioan Tudosa - Milpitas CA, US
Rajiv Yadav Ranjan - San Jose CA, US

Assignee:

Avalanche Technology, Inc. - Fremont CA

International Classification:

H01L 43/02

US Classification:

257421

Abstract:

A spin-torque transfer magnetic random access memory (STTMRAM) element employed to store a state based on the magnetic orientation of a free layer, the STTMRAM element is made of a first perpendicular free layer (PFL) including a first perpendicular enhancement layer (PEL). The first PFL is formed on top of a seed layer. The STTMRAM element further includes a barrier layer formed on top of the first PFL and a second perpendicular reference layer (PRL) that has a second PEL, the second PRL is formed on top of the barrier layer. The STTMRAM element further includes a capping layer that is formed on top of the second PRL.

US Patent:

20130286723, Oct 31, 2013

Filed:

Jun 26, 2013

Appl. No.:

13/928263

Inventors:

Yiming Huai - Pleasanton CA, US
Rajiv Yadav Ranjan - San Jose CA, US
Jing Zhang - Los Altos CA, US

International Classification:

G11C 11/16
H01L 43/02

US Classification:

365158, 257421

Abstract:

A spin toque transfer magnetic random access memory (STTMRAM) element comprises a reference layer, which can be a single layer structure or a synthetic multi-layer structure, formed on a substrate, with a fixed perpendicular magnetic component. A junction layer is formed on top of the reference layer and a free layer is formed on top of the junction layer with a perpendicular magnetic orientation, at substantially its center of the free layer and switchable. A spacer layer is formed on top of the free layer and a fixed layer is formed on top of the spacer layer, the fixed layer has a fixed perpendicular magnetic component opposite to that of the reference layer. The magnetic orientation of the free layer switches relative to that of the fixed layer. The perpendicular magnetic components of the fixed layer and the reference layer substantially cancel each other and the free layer has an in-plane edge magnetization field.

US Patent:

20130337582, Dec 19, 2013

Filed:

Jul 30, 2013

Appl. No.:

13/954673

Inventors:

Yiming Huai - Pleasanton CA, US
Jing Zhang - Los Altos CA, US
Yadav Ranjan - San Jose CA, US
Parviz Keshtbod - Los Altos Hills CA, US
Roger K. Malmhall - San Jose CA, US

Assignee:

Avalanche Technology Inc. - Fremont CA

International Classification:

H01L 43/12

US Classification:

438 3

Abstract:

Various embodiments of the invention relate to etching processes used in fabrication of MTJ cells in an MRAM device. The various embodiments can be used in combination with each other. The first embodiment adds a hard mask buffer layer between a hard mask and a top electrode. The second embodiment uses a multilayered etching hard mask. The third embodiment uses a multilayered top electrode structure including a first Cu layer under a second layer such as Ta. The fourth embodiment is a two-phase etching process used for the bottom electrode to remove re-deposited material while maintaining a more vertical sidewall etching profile. In the first phase the bottom electrode layer is removed using carbonaceous reactive ion etching until the endpoint. In the second phase an inert gas and/or oxygen plasma is used to remove the polymer that was deposited during the previous etching processes.

US Patent:

20140027697, Jan 30, 2014

Filed:

Jun 19, 2013

Appl. No.:

13/921481

Inventors:

Yiming Huai - Pleasanton CA, US
Jing Zhang - Los Altos CA, US
Rajiv Yadav Ranjan - San Jose CA, US
Roger Klas Malmhall - San Jose CA, US

International Classification:

H01L 43/02

US Classification:

257 1

Abstract:

A STTMRAM element includes a magnetization layer made of a first free layer and a second free layer, separated by a non-magnetic separation layer (NMSL), with the first and second free layers each having in-plane magnetizations that act on each other through anti-parallel coupling. The direction of the magnetization of the first and second free layers each is in-plane prior to the application of electrical current to the STTMRAM element and thereafter, the direction of magnetization of the second free layer becomes substantially titled out-of-plane and the direction of magnetization of the first free layer switches. Upon electrical current being discontinued to the STTMRAM element, the direction of magnetization of the second free layer remains in a direction that is substantially opposite to that of the first free layer.

US Patent:

20140042567, Feb 13, 2014

Filed:

Aug 10, 2012

Appl. No.:

13/572197

Inventors:

Dong Ha Jung - Pleasanton CA, US
Kimihiro Satoh - Beaverton OR, US
Jing Zhang - Los Altos CA, US
Yuchen Zhou - San Jose CA, US
Yiming Huai - Pleasanton CA, US

International Classification:

H01L 43/12
H01L 43/02

US Classification:

257421, 438 3, 257E43001, 257E43006

Abstract:

Use of a multilayer etching mask that includes a stud mask and a removable spacer sleeve for MTJ etching to form a bottom electrode that is wider than the rest of the MTJ pillar is described. The first embodiment of the invention described includes a top electrode and a stud mask. In the second and third embodiments the stud mask is a conductive material and also serves as the top electrode. In embodiments after the stud mask is formed a spacer sleeve is formed around it to initially increase the masking width for a phase of etching. The spacer is removed for further etching, to create step structures that are progressively transferred down into the layers forming the MTJ pillar. In one embodiment the spacer sleeve is formed by net polymer deposition during an etching phase.