Heusler-alloy and ferrimagnet based magnetic domain-wall devices for artificial neural network applications
AssigneeInternational Business Machines Corporation
InventorsChing-Tzu Chen, See-Hun Yang
Life of this patent
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Abstract
A synapse device includes a perpendicularly magnetized ferrimagnetic racetrack layer, a tunneling barrier layer disposed on the racetrack layer and a reference layer including a perpendicular magnetic alloy. The racetrack layer, the tunneling layer and the reference layer have a channel portion and contact pad portions. First and second contacts are provided over the contact pad portions, and a third contact is provided over the channel portion, wherein the first and second contacts are electrically isolated from the third contact.
Claims20
A synapse device, comprising:
- a perpendicularly magnetized ferrimagnet racetrack layer;
- a tunneling barrier layer disposed on the racetrack layer;
- a reference layer including a perpendicular magnetic alloy;
- the racetrack layer, the tunneling layer and the reference layer having a channel portion and contact pad portions;
- first and second contacts provided over the contact pad portions;
- and
- a third contact provided over the channel portion, wherein the first and second contacts are electrically isolated from the third contact.
A neural network device, comprising:
- a conductive grid having first conductive lines, second conductive lines and third conductive lines wherein the first conductive lines are disposed transversely to the second conductive lines and third conductive lines;
- and
- crosspoint synapse devices coupled to the first, second and third conductive lines at conductive line intersection points, the crosspoint synapse devices, each including:
- a perpendicularly magnetized ferrimagnet racetrack layer;
- a tunneling barrier layer disposed on the racetrack layer;
- and
- a reference layer including a perpendicular magnetic alloy;
- the racetrack layer, the tunneling layer and the reference layer of each crosspoint synapse device having a channel portion contact coupled to a third conductive line and contact pad contacts coupled to a respective first and second conductive lines, wherein the contact pad contacts are electrically isolated from the channel portion contact.
A method for forming a synapse device, comprising:
- blanket depositing a stack of layers, on a substrate, including a perpendicularly magnetized ferrimagnet racetrack layer, a tunneling barrier layer on the racetrack layer and a reference layer including a perpendicular magnetic alloy;
- defining a mesa structure from the stack of layers having a channel portion and contact portions on opposing ends, by a patterning process, wherein the contact pad portions include a width at least three times a width of the channel portion;
- forming a sidewall spacer around the mesa structure;
- depositing a conductive material to form first, second and third contacts where the first and second contacts are formed over the contact pad portions and the third contact is formed over the channel portion;
- and
- patterning the conductive material and the reference layer such that the reference layer of the contact pad portions is isolated from the reference layer of the channel portion.
Dependencies are inferred from the claim text.