Spin transfer MRAM device with novel magnetic free layer
AssigneeMagIC Technologies, Inc.
InventorsYimin Guo, Cheng T. Horng, Ru-Ying Tong
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Abstract
A CPP MTJ MRAM element utilizes transfer of spin angular momentum as a mechanism for changing the magnetic moment direction of a free layer. The device includes a tunneling barrier layer of MgO and a non-magnetic CPP layer of Cu or Cr and utilizes a novel free layer comprising a thin layer of Ta or Hf sandwiched by layers of CoFeB. The device is characterized by values of DR/R between approximately 95% and 105%.
Claims27
An MTJ MRAM device operating in a CPP configuration and utilizing the transfer of conduction electron spin angular momentum to change a free layer magnetization direction, comprising:
- a substrate;
- an MTJ element formed on said substrate, said element comprising a vertically stacked lamination of horizontal parallel layers including, therein, in the following order, an antiferromagnetic pinning layer, a pinned layer, a reference layer, a tunneling barrier layer, the free layer, a first conducting non-magnetic layer and a pinned drive layer, and wherein
- said free layer is a three layer laminate further comprising two layers of ferromagnetic material with a thin, second conducting non-magnetic layer formed therebetween and wherein,
- said ferromagnetic layers are magnetized in parallel directions within the horizontal plane of their formation, said directions being maintained by exchange coupling and wherein,
- said ferromagnetic layers are formed with a uni-axial magnetic anisotropy to render said magnetization directions thermally stable and wherein,
- a current of conduction electrons in the vertical direction can change the direction of magnetization of said free layer by both reflection and transmission, thereby minimizing the strength of the current.
A method of forming an MTJ MRAM device operating in a CPP configuration and utilizing the transfer of conduction electron spin angular momentum to change a free layer magnetization direction, comprising:
- providing a substrate;
- forming an MTJ element on said substrate, said element comprising a vertically stacked lamination formed of horizontal parallel layers including, therein, in the following order, an antiferromagnetic pinning layer, a pinned layer, a reference layer, a tunneling barrier layer, the free layer, a first conducting non-magnetic layer and a pinned drive layer, and wherein
- said free layer is a three layer laminate further comprising two layers of ferromagnetic material and having a thin, second conducting, non-magnetic layer formed therebetween and wherein,
- said ferromagnetic layers are magnetized in parallel directions within the horizontal plane of their formation, said directions being maintained by exchange coupling and wherein,
- said ferromagnetic layers are formed with a uni-axial magnetic anisotropy to render said magnetization directions thermally stable and wherein,
- a current of conduction electrons in the vertical direction can change the direction of magnetization of said free layer by both transmission and reflection, thereby minimizing the strength of the required current.
Dependencies are inferred from the claim text.