Srinivas Vr Pietambaram

US Patent:

6831312, Dec 14, 2004

Filed:

Aug 30, 2002

Appl. No.:

10/232164

Inventors:

Jon M. Slaughter - Tempe AZ
Renu W. Dave - Chandler AZ
Srinivas V. Pietambaram - Chandler AZ

Assignee:

Freescale Semiconductor, Inc. - Austin TX

International Classification:

H01L 31119

US Classification:

257295, 257489

Abstract:

An amorphous layer of a cobalt iron-based (CoFe-based) magnetic alloy suitable for use in magnetoelectronic devices is disclosed. In the most preferred embodiments of the present invention, at least one amorphous layer is provided in an MTJ stack to increase the smoothness of the various layers in the MTJ stack while also enhancing the magnetic performance of the resulting device. Additionally, the alloys of the present invention are also useful in cladding applications to provide electrical flux containment for signal lines in magnetoelectronic devices and as a material for fabricating write heads.

US Patent:

6946697, Sep 20, 2005

Filed:

Dec 18, 2003

Appl. No.:

10/740338

Inventors:

Srinivas V. Pietambaram - Chandler AZ, US
Renu W. Dave - Chandler AZ, US
Jon M. Slaughter - Tempe AZ, US
Jijun Sun - Chandler AZ, US

Assignee:

Freescale Semiconductor, Inc. - Austin TX

International Classification:

H01L029/76

US Classification:

257295, 257421, 365158, 365171, 365173

Abstract:

A magnetic tunnel junction (MTJ), which is useful in magnetoresistive random access memories (MRAMs), has a free layer which is a synthetic antiferromagnet (SAF) structure. This SAF is composed of two ferromagnetic layers that are separated by a coupling layer. The coupling layer has a base material that is non-magnetic and also other materials that improve thermal endurance, control of the coupling strength of the SAF, and magnetoresistance ratio (MR). The preferred base material is ruthenium and the preferred other material is tantalum. Furthering these benefits, cobalt-iron is added at the interface between the tantalum and one of the ferromagnetic layers. Also the coupling layer can have even more layers and the materials used can vary. Also the coupling layer itself can be an alloy.

US Patent:

7067331, Jun 27, 2006

Filed:

Nov 3, 2004

Appl. No.:

10/980930

Inventors:

Jon M. Slaughter - Tempe AZ, US
Renu W. Dave - Chandler AZ, US
Srinivas V. Pietambaram - Chandler AZ, US

Assignee:

Freescale Semiconductor, Inc. - Austin TX

International Classification:

H01L 21/00

US Classification:

438 3, 438 73

Abstract:

An amorphous layer of a cobalt iron-based (CoFe-based) magnetic alloy suitable for use in magnetoelectronic devices is disclosed. In the most preferred embodiments of the present invention, at least one amorphous layer is provided in an MTJ stack to increase the smoothness of the various layers in the MTJ stack while also enhancing the magnetic performance of the resulting device. Additionally, the alloys of the present invention are also useful in cladding applications to provide electrical flux containment for signal lines in magnetoelectronic devices and as a material for fabricating write heads.

US Patent:

7226796, Jun 5, 2007

Filed:

Jul 15, 2005

Appl. No.:

11/182149

Inventors:

Srinivas V. Pietambaram - Chandler AZ, US
Renu W. Dave - Chandler AZ, US
Jon M. Slaughter - Tempe AZ, US
Jijun Sun - Chandler AZ, US

Assignee:

Freescale Semiconductor, Inc. - Austin TX

International Classification:

H01L 21/00
H01L 29/76

US Classification:

438 3, 257295, 257E21665, 365158, 365171, 365173, 4288112

Abstract:

A magnetic tunnel junction (MTJ), which is useful in magnetoresistive random access memories (MRAMs), has a free layer which is a synthetic antiferromagnet (SAF) structure. This SAF is composed of two ferromagnetic layers that are separated by a coupling layer. The coupling layer has a base material that is non-magnetic and also other materials that improve thermal endurance, control of the coupling strength of the SAF, and magnetoresistance ratio (MR). The preferred base material is ruthenium and the preferred other material is tantalum. Furthering these benefits, cobalt-iron is added at the interface between the tantalum and one of the ferromagnetic layers. Also the coupling layer can have even more layers and the materials used can vary. Also the coupling layer itself can be an alloy.

US Patent:

7285835, Oct 23, 2007

Filed:

Feb 24, 2005

Appl. No.:

11/066884

Inventors:

Nicholas D. Rizzo - Gilbert AZ, US
Renu Dave - Chandler AZ, US
Jon M. Slaughter - Tempe AZ, US
Srinivas V. Pietambaram - Chandler AZ, US

Assignee:

Freescale Semiconductor, Inc. - Austin TX

International Classification:

H01L 43/00

US Classification:

257421, 257295, 257E27006, 438 3, 365171

Abstract:

Low power magnetoelectronic device structures and methods for making the same are provided. One magnetoelectronic device structure () comprises a programming line (), a magnetoelectronic device () magnetically coupled to the programming line, and an enhanced permeability dielectric material () disposed adjacent the magnetoelectronic device. The enhanced permeability dielectric material has a permeability no less than approximately 1. 5. A method for making a magnetoelectronic device structure is also provided. The method comprises fabricating a magnetoelectronic device () and depositing a conducting line (). A layer of enhanced permeability dielectric material () having a permeability no less than approximately 1. 5 is formed, wherein after the step of fabricating a magnetoelectronic device and the step of depositing a conducting line, the layer of enhanced permeability dielectric material is situated adjacent the magnetoelectronic device.

US Patent:

7445943, Nov 4, 2008

Filed:

Oct 19, 2006

Appl. No.:

11/584411

Inventors:

Kenneth H. Smith - Chandler AZ, US
Brian R. Butcher - Queen Creek AZ, US
Gregory W. Grynkewich - Gilbert AZ, US
Srinivas V. Pietambaram - Chandler AZ, US
Nicholas D. Rizzo - Gilbert AZ, US

Assignee:

Everspin Technologies, Inc. - Chandler AZ

International Classification:

H01L 21/00

US Classification:

438 3, 438733, 257E2117, 257E21208, 257E21209, 257E21218, 257E21231, 257E21646

Abstract:

Methods and apparatus are provided for magnetoresistive memories employing magnetic tunnel junction (MTJ). The apparatus comprises a MTJ (), first () and second () electrodes coupled, respectively, to first () and second () magnetic layers of the MTJ (), first () and second () write conductors magnetically coupled to the MTJ () and spaced apart from the first () and second () electrodes, and at least one etch-stop layer () located between the first write conductor () and the first electrode (), having an etch rate in a reagent for etching the MTJ () and/or the first electrode () that is at most % of the etch rate of the MTJ () and/or first conductor () to the same reagent, so as to allow portions of the MTJ () and first electrode () to be removed without affecting the underlying first write conductor (). In a further embodiment, a second etch-stop layer () is located between the second electrode () and the second write conductor (). Improved yield and performance are obtained.

US Patent:

7635902, Dec 22, 2009

Filed:

Oct 4, 2007

Appl. No.:

11/867189

Inventors:

Nicholas D. Rizzo - Gilbert AZ, US
Renu Dave - Chandler AZ, US
Jon M. Slaughter - Tempe AZ, US
Srinivas V. Pietambaram - Chandler AZ, US

Assignee:

Everspin Technologies, Inc. - Chandler AZ

International Classification:

H01L 29/82

US Classification:

257421, 257295, 257E27006, 438 3, 977838, 977933, 365171

Abstract:

Low power magnetoelectronic device structures and methods for making the same are provided. One magnetoelectronic device structure () comprises a programming line (), a magnetoelectronic device () magnetically coupled to the programming line, and an enhanced permeability dielectric material () disposed adjacent the magnetoelectronic device. The enhanced permeability dielectric material has a permeability no less than approximately 1. 5. A method for making a magnetoelectronic device structure is also provided. The method comprises fabricating a magnetoelectronic device () and depositing a conducting line (). A layer of enhanced permeability dielectric material () having a permeability no less than approximately 1. 5 is formed, wherein after the step of fabricating a magnetoelectronic device and the step of depositing a conducting line, the layer of enhanced permeability dielectric material is situated adjacent the magnetoelectronic device.

US Patent:

7683445, Mar 23, 2010

Filed:

Apr 25, 2007

Appl. No.:

11/740066

Inventors:

Srinivas V. Pietambaram - Chandler AZ, US
Nicholas D. Rizzo - Gilbert AZ, US
Jon M. Slaughter - Tempe AZ, US

Assignee:

Everspin Technologies, Inc. - Chandler AZ

International Classification:

H01L 29/82

US Classification:

257421, 257295, 257E27006, 438 3, 977838, 977933, 365171

Abstract:

Low power magnetoelectronic device structures and methods therefore are provided. The magnetoelectronic device structure () comprises a programming line (), a magnetoelectronic device () magnetically coupled to the programming line (), and an enhanced permeability dielectric (EPD) material () disposed adjacent the magnetoelectronic device. The EPD material () comprises multiple composite layers () of magnetic nano-particles () embedded in a dielectric matrix (). The composition of the composite layers is chosen to provide a predetermined permeability profile. A method for making a magnetoelectronic device structure is also provided. The method comprises fabricating the magnetoelectronic device () and depositing the programming line (). The EPD material () comprising the multiple composite layers () is formed around the magnetoelectronic device () and/or between the device () and the programming line (). The presence of the EPD structure () in proximity to the programming line () and/or the magnetoelectronic device () reduces the required programming current.