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US 8,558,331 B2Granted
Magnetic tunnel junction device
AssigneeQUALCOMM Incorporated
InventorsXiaochun Zhu, Seung H. Kang, Xia Li, Kangho Lee
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AssigneeQUALCOMM Incorporated
InventorsXiaochun Zhu, Seung H. Kang, Xia Li, Kangho Lee
Estimating the term…
A system and method of manufacturing and using a magnetic tunnel junction device is disclosed. In a particular embodiment, a magnetic tunnel junction device includes a first free layer and second free layer. The magnetic tunnel junction also includes a spin torque enhancement layer. The magnetic tunnel junction device further includes a spacer layer between the first and second free layers that includes a material and has a thickness that substantially inhibits exchange coupling between the first and second free layers. The first and second free layers are magneto-statically coupled.
A magnetic tunnel junction device, comprising:
An apparatus, comprising:
A method of manufacturing a magnetic tunnel junction device, the method comprising:
A method comprising:
A non-transitory computer readable tangible medium storing instructions executable by a computer, the instructions comprising:
A method comprising:
A method comprising;
A method comprising:
A method comprising:
Dependencies are inferred from the claim text.
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Galvanomagnetic devices: constructional details
Galvanomagnetic devices: manufacture or treatment
Galvanomagnetic devices: magnetoresistive devices
Constructional details: materials of the active region
About 5 years 3 months of term left · ends 23 Jan 2032 (estimated)
The present disclosure is generally related to magnetic tunnel junction devices.
Magnetic Random Access Memory (MRAM) is a nonvolatile memory technology that uses magnetization to represent stored data. An MRAM generally includes a plurality of magnetic cells in an array. Each cell typically represents one bit of data. A cell includes a magnetic element, such as a magnetic tunnel junction (MTJ).
Ferromagnetic plates of an MTJ typically include a free layer and a pinned layer separated by a thin tunneling barrier layer. The plates are associated with a magnetization direction (or orientation of magnetic moments). In the free layer, the magnetization direction is free to rotate. An anti-ferromagnetic layer may be used to fix the magnetization of the pinned layer in a particular direction. A bit is written to the MTJ by changing the magnetization direction of one of the ferromagnetic plates of the MTJ. The resistance of the MTJ depends upon the orientations of the magnetic moments of the free layer and the pinned layer. By applying a switching current to the MTJ element, the magnetic polarization of the MTJ element can be changed from a logic “1” state to a logic “0” state or vice versa.
FIG. 1 is a cross sectional view of an embodiment of a magnetic tunnel junction (MTJ) device in a first state and in a second state;
FIG. 2 is a cross sectional view of a first embodiment of a dual free layer structure of an embodiment of an MTJ device;
FIG. 3 shows a cross sectional view of a second embodiment and a third embodiment of a portion of a representative MTJ device;
FIG. 1 is a cross sectional view of an embodiment of an MTJ device in a first state 120, (logic “1”), and in a second state 130, (logic “0”). The embodiment of FIG. 1 includes multiple layers above a substrate 101. The substrate 101 may be a semiconductor substrate including, for example, silicon, germanium, or a compound semiconductor material. A first layer 102 above the substrate is a bottom layer which may form an electrode and include Ta. Ta provides better growing texture for an Anti-Ferromagnetic (AFM) pinning layer, and provides a smooth surface for growing the MTJ. The bottom layer can be composed of multiple layers of different materials. A layer 103 is an Anti-Ferromagnetic (AFM) pinning layer. The AFM pinning layer 103 acts to pin the magnetic moments in layers 104 and 108. The AFM pinning layer 103 may include an anti-ferromagnetic material such as MnPt, IrMn, FeMn, or NiO. An example thickness of the AFM pinning layer 103 is 15 nm. Other thicknesses may be employed for the AFM pinning layer 103.
The layers 104, 106 and 108 form a Synthetic Anti-Ferromagnetic (SAF) layer. The layer 104 is pinned by layer 103 by an exchange coupling mechanism.
The layer 108 is pinned to layer 104 by exchange coupling through a spacer layer 106. The spacer layer 106 may be Ru, Rh, or Cr or other material that does not substantially inhibit exchange coupling. The layers 104 and 108 are ferromagnetic and may include Fe, Ni, Co, or B, or a combination of these elements, such as, for example, CoFeB. The magnetic moments in layers 104 and 108 are anti-parallel, thus forming an anti-ferromagnetic layer. An example thickness of the SAF layer is 2 nm (nanometers) for layer 104, 0.9 nm for layer 106, 2 nm for layer 108. Other thicknesses may be employed for the SAF layer.