# US 10,319,900 B1 · Perpendicular magnetic tunnel junction device with precessional spin current layer having a modulated moment density > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,319,900 B1 - Document ID: US10319900B1 - Status: Granted - Kind: B1 - Application number: 15/859,381 - Filed: 2017-12-30 - Published: 2019-07-04 - Granted: 2019-06-11 - Earliest claimed: 2017-12-30 - Assignees: Spin Memory, Inc. - Applicants: Spin Memory, Inc. - Inventors: Manfred Ernst Schabes; Mustafa Michael Pinarbasi; Bartlomiej Adam Kardasz - Web page: https://patentgrep.com/patent/US10319900B1 ## CPC - H10N 50/80: Constructional details - G11C 11/161: {details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell} - H01F 10/3254: {the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]} - H01F 10/3272: {by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets} - H01F 10/3286: {Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy} - H01F 10/329: {Spin-exchange coupled multilayers wherein the magnetisation of the free layer is switched by a spin-polarised current, e.g. spin torque effect} - H01F 41/302: {for applying spin-exchange-coupled multilayers, e.g. nanostructured superlattices (spin-exchange-coupled multilayers H01F10/32)} - H01F 41/308: {lift-off processes, e.g. ion milling, for trimming or patterning} - H10N 50/01: Manufacture or treatment - H10N 50/10: Magnetoresistive devices - H10N 50/85: Materials of the active region - H10B 61/00: Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - G11C: STATIC STORES (semiconductor memory devices H10B) - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - H10B: ELECTRONIC MEMORY DEVICES ## Abstract A magnetoresistive random-access memory (MRAM) is disclosed. The MRAM device includes a perpendicular magnetic tunnel junction device having a reference layer, a free layer, and a precessional spin current magnetic layer. The precessional spin current magnetic layer has a non-uniform moment density, and may have a moment density at its center that is greater than a moment density at its perimeter. The device is designed to provide control over the injection of stray fields and the electronic coupling between the precessional spin current magnetic layer and the free layer. Switching speed, switching current, and thermal barrier height for the device can be adjusted. The decreased moment density at the perimeter of the precessional spin current layer helps to stabilize the free layer when the effective magnetic field of the precessional spin current layer is high. Spin accumulation can be increased near the center of the precessional spin current layer, helping to switch the free layer. ## Claims ### Claim 1 A magnetic device, comprising: a first synthetic antiferromagnetic structure in a first plane having a magnetization vector that is perpendicular to the first plane and having a fixed magnetization direction; an antiferromagnetic coupling layer in a second plane and disposed above the first synthetic antiferromagnetic structure; a second synthetic antiferromagnetic structure in a third plane and disposed over the antiferromagnetic coupling layer; a magnetic reference layer in a fourth plane and disposed over the second synthetic antiferromagnetic structure, the magnetic reference layer having a magnetization vector that is perpendicular to the fourth plane and having a fixed magnetization direction; a non-magnetic tunnel barrier layer in a fifth plane and disposed over the magnetic reference layer; a free magnetic layer disposed in a sixth plane over the non-magnetic tunnel barrier layer, the free magnetic layer having a magnetization vector that is perpendicular to the sixth plane and having a magnetization direction that can switch between a first magnetization direction to a second magnetization direction, the magnetic reference layer, the non-magnetic tunnel barrier layer and the free magnetic layer forming a magnetic tunnel junction; and a precessional spin current magnetic layer having a non-uniform moment density, the precessional spin current magnetic layer disposed in a seventh plane that is physically separated from the free magnetic layer and coupled to the free magnetic layer by a filter coupling layer that may induce ferromagnetic or antiferromagnetic coupling between the free magnetic layer and the filter layer. ### Claim 2 (depends on 1) The magnetic device of claim 1, wherein a first region includes a center of the precessional spin current magnetic layer, wherein a second region includes a perimeter of the precessional spin current magnetic layer, and wherein a moment density of the first region is greater than a moment density of the second region. ### Claim 3 (depends on 2) The magnetic device of claim 2, wherein the precessional spin current magnetic layer is formed from CoxFeyBz, where y is in the range 40% to 70%, z is in the range 18% to 21%, and x+y+z=100%. ### Claim 4 (depends on 3) The magnetic device of claim 3, wherein a percentage of Fe in the first region is greater than a percentage of Fe in the second region. ### Claim 5 (depends on 4) The magnetic device of claim 4, wherein a ratio of the percentage of Fe in the first region to the percentage of Fe in the second region is in the range of 1.15 to 1.75. ### Claim 6 (depends on 2) The magnetic device of claim 2, wherein the second region is formed from CoxFeyBz, where y is in the range 40% to 70%, z is in the range 18% to 21%, and x+y+z=100%, and wherein the first region is formed from Fe. ### Claim 7 (depends on 2) The magnetic device of claim 2, wherein the second region is formed from CoxFeyBz, where y is in the range 40% to 70%, z is in the range 18% to 21%, and x+y+z=100%, and wherein the first region is formed from FeCo. ### Claim 8 (depends on 1) The magnetic device of claim 1 further comprising a first central region and a plurality of annular regions disposed around the central region, each annular region having a moment density that is less than a moment density of each region disposed therein. ### Claim 9 (depends on 8) The magnetic device of claim 8, wherein the precessional spin current magnetic layer is formed from CoxFeyBz, where y is in the range 40% to 70%, z is in the range 18% to 21%, and x+y+z=100%. ### Claim 10 (depends on 9) The magnetic device of claim 9, wherein a percentage of Fe in the each annular region is less than a percentage of Fe in each region disposed therein. ### Claim 11 A magnetic device, comprising: a magnetic reference layer in a first plane, the magnetic reference layer having a magnetization vector that is perpendicular to the first plane and having a fixed magnetization direction; a non-magnetic tunnel barrier layer in a second plane and disposed over the magnetic reference layer; a free magnetic layer disposed in a third plane over the non-magnetic tunnel barrier layer, the free magnetic layer having a magnetization vector that is perpendicular to the third plane and having a magnetization direction that can switch between a first magnetization direction to a second magnetization direction, the magnetic reference layer, the non-magnetic tunnel barrier layer and the free magnetic layer forming a magnetic tunnel junction; and a precessional spin current magnetic layer having a non-uniform moment density, the precessional spin current magnetic layer disposed in a fourth plane that is physically separated from the free magnetic layer and coupled to the free magnetic layer by a filter coupling layer that may induce ferromagnetic or antiferromagnetic coupling between the free magnetic layer and the filter layer. ### Claim 12 (depends on 11) The magnetic device of claim 11, wherein a first region includes a center of the precessional spin current magnetic layer, wherein a second region includes a perimeter of the precessional spin current magnetic layer, and wherein a moment density of the first region is greater than a moment density of the second region. ### Claim 13 (depends on 12) The magnetic device of claim 12, wherein the precessional spin current magnetic layer is formed from CoxFeyBz, where y is in the range 40% to 70%, z is in the range 18% to 21%, and x+y+z=100%. ### Claim 14 (depends on 13) The magnetic device of claim 13, wherein a percentage of Fe in the first region is greater than a percentage of Fe in the second region. ### Claim 15 (depends on 14) The magnetic device of claim 14, wherein a ratio of the percentage of Fe in the first region to the percentage of Fe in the second region is in the range of 1.15 to 1.75. ### Claim 16 (depends on 12) The magnetic device of claim 12, wherein the second region is formed from CoxFeyBz, where y is in the range 40% to 70%, z is in the range 18% to 21%, and x+y+z=100%, and wherein the first region is formed from Fe. ### Claim 17 (depends on 12) The magnetic device of claim 12, wherein the second region is formed from CoxFeyBz, where y is in the range 40% to 70%, z is in the range 18% to 21%, and x+y+z=100%, and wherein the first region is formed from FeCo. ### Claim 18 (depends on 11) The magnetic device of claim 11 further comprising a first central region and a plurality of annular regions disposed around the central region, each annular region having a moment density that is less than a moment density of each region disposed therein. ### Claim 19 (depends on 18) The magnetic device of claim 18, wherein the precessional spin current magnetic layer is formed from CoxFeyBz, where y is in the range 40% to 70%, z is in the range 18% to 21%, and x+y+z=100%. ### Claim 20 (depends on 19) The magnetic device of claim 19, wherein a percentage of Fe in the each annular region is less than a percentage of Fe in each region disposed therein. ### Claim 21 A method for manufacturing a magnetic device comprising the steps of: providing a magnetic tunnel junction including a magnetic reference layer, a non-magnetic tunnel barrier layer, and a free magnetic layer; depositing a filter coupling layer over the free magnetic layer; depositing a first material to form a precessional spin current magnetic layer over the filter coupling layer; forming a partial pillar that includes the precessional spin current magnetic layer; depositing a second material to further form the precessional spin current magnetic layer, the second material having a moment density that is less than a moment density of the first material; depositing a hard mask layer over the precessional spin current magnetic layer; forming a pillar that includes the precessional spin current magnetic layer, the filter coupling layer, the free magnetic layer, the non-magnetic tunnel barrier layer, and the magnetic reference layer such that the precessional spin current magnetic layer has a diameter that is different from a diameter of the free magnetic layer; and depositing an electrical contact layer over the precessional spin current layer.