International Business Machines Corporation

Christopher Safranski

Jonathan Zanhong Sun

Pouya Hashemi

A magnetic random access memory (MRAM) apparatus and method are provided. The apparatus includes a magnetic tunnel junction (MTJ) stack; a spin-orbit-torque (SOT) layer that underlies the MTJ stack; and a dielectric pillar that underlies the SOT layer and the MTJ stack. The SOT layer has a stepped profile. The method includes forming a dielectric base of a first dielectric material and a dielectric pillar of a second dielectric material, wherein the dielectric pillar protrudes from the dielectric base, forming a first intermediate structure by depositing a first layer of conductive material onto the dielectric base, sufficiently thick to cover the pillar and the base, forming a planarized structure by planarizing the first intermediate structure to reveal the pillar, and depositing a second layer of spin-orbit-torque metal onto the planarized structure.

Spin-orbit-torque (SOT) MRAM with doubled layer of SOT metal

A memory device includes a first terminal and a second terminal; a magnetic tunnel junction coupled to the second terminal; wherein the magnetic tunnel junction comprises a magnetic free layer, and the magnetic tunnel junction is configured to be displaced by a plurality of distances from a center position of the device; a nonmagnetic metallic spin harvesting conductor coupled to the magnetic tunnel junction; wherein the nonmagnetic metallic spin harvesting conductor has a lateral dimension that is larger than that of the magnetic tunnel junction; an electrically insulating spin conductor coupled to the nonmagnetic metallic spin harvesting conductor; wherein the electrically insulating spin conductor has relatively less electrical conductivity than the nonmagnetic metallic spin harvesting conductor; wherein the nonmagnetic metallic spin harvesting conductor collects spin current from the electrically insulating spin conductor; and a spin orbit conduction channel coupled to the electrically insulating spin conductor and to the first terminal.

Memory device with spin-harvesting structure

A magnetic memory device including a magnetic tunnel junction (MTJ) pillar containing a stable resonant synthetic antiferromagnet (SAF) reference layered structure in which the ferromagnetic resonance characteristics of a polarizing magnetic layer of the SAF reference layered structure are substantially matched to at least a first magnetic reference layer within the SAF reference layered structure. By substantially matching the ferromagnetic resonance characteristics of the polarizing magnetic layer to at least the first magnetic reference layer, a MTJ pillar is provided in which the dynamic stability of the polarizing magnetic layer can be improved, and undesirable magnetic reference layer instability related write-errors can be mitigated.

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Yorktown Heights, NY, United States of America

Christopher Safranski