Hitachi Global Storage Technologies Netherlands B.v.

International Business Machines Corporation

Samsung Electronics Co., Ltd.

Headway Technologies, Incorporated

Taiwan Semiconductor Manufacturing Comp. Ltd.

Magic Technologies, Inc.

Robert Beach

David John Seagle

Ru-Ying Tong

Vladimir Nikitin

Yu-Jen Wang

Guenole Jan

Satoru Araki

Witold Kula

Cheng Tzong Horng

Dmytro Apalkov

Po-Kang Wang

Tai Min

Wipul Jayasekara

Howard Gordon Zolla

Ying Hong

Alexey Vasilyevitch Khvalkovskiy

Guangli Liu

Jila Tabib

Arley Cleveland Marley

Sebastian Schafer

Mary Kathryn Gutberlet

Zheng Duan

Quang Le

Daniele Mauri

Chyu-Jiuh Torng

Bruce Alvin Gurney

Matthew Joseph Carey

Jui-lung Li

David Eugene Heim

Marie-Claire Cyrille

Roman Chepulskyy

Dustin William Erickson

Thomas L Leong

Timothy James Minvielle

Volodymyr Voznyuk

Ilya Krivorotov

Chengcen Sha

A synthetic antiferromagnetic structure for a spintronic device is disclosed and has an FL2/Co or Co alloy/antiferromagnetic coupling/Co or Co alloy/CoFeB configuration where FL2 is a ferromagnetic free layer with intrinsic PMA. Antiferromagnetic coupling is improved by inserting a Co or Co alloy dusting layer on top and bottom surfaces of the antiferromagnetic coupling layer. The FL2 layer may be a L10 ordered alloy, a rare earth-transition metal alloy, or an (A1/A2)n laminate where A1 is one of Co, CoFe, or an alloy thereof, and A2 is one of Pt, Pd, Rh, Ru, Ir, Mg, Mo, Os, Si, V, Ni, NiCo, and NiFe, or A1 is Fe and A2 is V. A method is also provided for forming the synthetic antiferromagnetic structure.

Minimal thickness synthetic antiferromagnetic (SAF) structure with perpendicular magnetic anisotropy for STT-MRAM

A synthetic antiferromagnetic structure for a spintronic device is disclosed and has an FL2/Co or Co alloy/antiferromagnetic coupling/Co or Co alloy/CoFeB configuration where FL2 is a ferromagnetic free layer with intrinsic PMA. Antiferromagnetic coupling is improved by inserting a Co or Co alloy dusting layer on top and bottom surfaces of the antiferromagnetic coupling layer. The FL2 layer may be a L10 ordered alloy, a rare earth-transition metal alloy, or an (A1/A2)laminate where A1 is one of Co, CoFe, or an alloy thereof, and A2 is one of Pt, Pd, Rh, Ru, Ir, Mg, Mo, Os, Si, V, Ni, NiCo, and NiFe, or A1 is Fe and A2 is V. A method is also provided for forming the synthetic antiferromagnetic structure.

A method for measuring a temperature of magnetic junction switchable using spin transfer. The magnetic junction includes at least one magnetic layer. The method includes measuring a temperature variation of at least one magnetic characteristic for the magnetic layer(s) versus temperature. The method also includes measuring a bias variation in the magnetic characteristic versus an electrical bias for the magnetic junction. This measurement is performed such that spin transfer torque-induced variation(s) in the magnetic characteristic(s) are accounted for. The temperature versus the electrical bias for the magnetic junction is determined based on the temperature variation and the bias variation.

Method and system for determining temperature using a magnetic junction

A method and apparatus determine an exchange stiffness of a free layer residing in a magnetic junction. The method includes performing spin torque ferromagnetic resonance (ST-FMR) measurements for the magnetic junction. The ST-FMR measurements indicate characteristic frequencies corresponding to spin wave modes in the free layer. The method also includes calculating the exchange stiffness of the free layer based upon the plurality of characteristic frequencies. In some embodiments, the magnetic junction resides on a wafer including other magnetic junctions for a device. The magnetic junctions may be arranged as a magnetic memory. The magnetic junction undergoing ST-FMR has a different aspect ratio than the magnetic junctions.

Method and apparatus for measuring exchange stiffness at a patterned device level

A synthetic antiferromagnetic (SAF) structure for a spintronic device is disclosed and has an FL2/AF coupling/CoFeB configuration where FL2 is a ferromagnetic free layer with intrinsic PMA. In one embodiment, AF coupling is improved by inserting a Co dusting layer on top and bottom surfaces of a Ru AF coupling layer. The FL2 layer may be a L10 ordered alloy, a rare earth-transition metal alloy, or an (A1/A2)laminate where A1 is one of Co, CoFe, or an alloy thereof, and A2 is one of Pt, Pd, Rh, Ru, Ir, Mg, Mo, Os, Si, V, Ni, NiCo, and NiFe, or A1 is Fe and A2 is V. A method is also provided for forming the SAF structure.

A method provides a magnetic junction having a top and sides. A first magnetic layer, a nonmagnetic spacer layer and a second magnetic layer are deposited. The nonmagnetic spacer layer is between the first and second magnetic layers. A free layer is one of the magnetic layers. A reference layer is the other of the magnetic layers. The second magnetic layer includes an amorphous magnetic layer having nonmagnetic constituent(s) that are glass-forming. An anneal is performed in a gas having an affinity for the nonmagnetic constituent(s). The gas includes at least one of first and second gases. The first gas forms a gaseous compound with the nonmagnetic constituent(s) The second gas forms a solid compound with the nonmagnetic constituent(s). The second gas is usable if the anneal is performed after the magnetic junction has been defined. The solid compound is at least on the sides of the magnetic junction.

Method and system for removing boron from magnetic junctions usable in spin transfer torque memory applications

A STT-RAM MTJ is disclosed with a MgO tunnel barrier formed by natural oxidation and containing an oxygen surfactant layer to form a more uniform MgO layer and lower breakdown distribution percent. A CoFeB/NCC/CoFeB composite free layer with a middle nanocurrent channel layer minimizes Jcwhile enabling thermal stability, write voltage, read voltage, and Hc values that satisfy 64 Mb design requirements. The NCC layer has RM grains in an insulator matrix where R is Co, Fe, or Ni, and M is a metal such as Si or Al. NCC thickness is maintained around the minimum RM grain size to avoid RM granules not having sufficient diameter to bridge the distance between upper and lower CoFeB layers. A second NCC layer and third CoFeB layer may be included in the free layer or a second NCC layer may be inserted below the Ru capping layer.

Structure and method to fabricate high performance MTJ devices for spin-transfer torque (STT)-RAM application

An STT MTJ cell is formed with a magnetic anisotropy of its free and reference layers that is perpendicular to their planes of formation. The reference layer of the cell is an SAF multilayered structure with a single magnetic domain to enhance the bi-stability of the magnetoresistive states of the cell. The free layer of the cell is etched back laterally from the reference layer, so that the fringing stray field of the reference layer is no more than 15% of the coercivity of the free layer and has minimal effect on the free layer.

STT-MRAM reference layer having substantially reduced stray field and consisting of a single magnetic domain

A synthetic antiferromagnetic (SAF) structure for a spintronic device is disclosed and has an AP2/antiferromagnetic (AF) coupling/CoFeB configuration. The SAF structure is thinned to reduce the fringing (Ho) field while maintaining high coercivity. The AP2 reference layer has intrinsic perpendicular magnetic anisotropy (PMA) and induces PMA in a thin CoFeB layer through AF coupling. In one embodiment, AF coupling is improved by inserting a Co dusting layer on top and bottom surfaces of a Ru AF coupling layer. When AP2 is (Co/Ni), and CoFeB thickness is 7.5 Angstroms, Ho is reduced to 125 Oe, Hc is 1000 Oe, and a balanced saturation magnetization-thickness product (Mst)=0.99 is achieved. The SAF structure may also be represented as FL2/AF coupling/CoFeB where FL2 is a ferromagnetic layer with intrinsic PMA.

A STT-RAM MTJ is disclosed with a MgO tunnel barrier formed by a NOX process, a CoFeB/FeSiO/CoFeB composite free layer with a middle nanocurrent channel layer to minimize Jc, and a Ru capping layer to enhance the spin scattering effect and increase dR/R. Good write margin is achieved by modifying the NOX process to afford a RA less than 10 ohm-&#x3bc;mand good read margin is realized with a dR/R of &#x3e;100% by annealing at 330&#xb0; C. or higher to form crystalline CoFeB free layers. The NCC thickness is maintained in the 6 to 10 Angstrom range to reduce Rp and avoid Fe(Si) granules from not having sufficient diameter to bridge the distance between upper and lower CoFeB layers. A FeSiO layer may be inserted below the Ru layer in the capping layer to prevent the Ru from causing a high damping constant in the upper CoFeB free layer.

Structure and method to fabricate high performance MTJ devices for spin-transfer torque (STT)-RAM

A wafer comprises a kerf region and a test chip. The kerf is a region in a wafer designated to be destroyed by chip dicing. The test chip is located within the kerf region and is configured to provide parametric data for a wafer fabrication process of a head. The test chip comprises a shield portion of a first shield layer electrically coupled to an element, a first pad within a second shield layer electrically coupled to the element, and a second pad within the second shield layer electrically coupled to the shield portion.

Wafer level testing

Test methods and components are disclosed for testing resistances of magnetoresistance (MR) sensors in read elements. Test components are fabricated on a wafer with a first test lead, a pseudo sensor, and a second test lead. The test leads and MR sensor are fabricated with similar processes as first shields, MR sensors, and second shields of read elements on the wafer. However, the pseudo sensor in the test component is fabricated with lead material (or another material having similar resistance properties) instead of an MR thin-film structure like an MR sensor. Forming the pseudo sensor from lead material causes the resistance of the pseudo sensor to be insignificant compared to the lead resistance. Thus, a resistance measurement of the test component represents the lead resistance of a read element. An accurate resistance measurement of an MR sensor in a read element may then be determined by subtracting the lead resistance.

Test components fabricated with pseudo sensors used for determining the resistance of an MR sensor

Test methods and components are disclosed for testing the quality of a fabrication process used to form read elements in magnetic heads. A wafer is populated with one or more test components along with magnetic heads. The test components are formed by the same or similar fabrication processes as the read elements, but do not include a conductive MR sensor between the test leads. By measuring the resistance of the test components, the formation of parasitic shunts can be identified in the test components, which may indicate the formation of parasitic shunts in the read elements. Thus, the quality of the fabrication process in forming read elements in magnetic head may be determined.

Verification of a fabrication process used to form read elements in magnetic heads

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Robert Beach