Spin orbit torque (SOT) memory devices and their methods of fabrication
A spin orbit torque (SOT) memory device includes a magnetic tunnel junction (MTJ) device with one end coupled with a first electrode and an opposite end coupled with a second electrode including a spin orbit torque material. In an embodiment, a second electrode is coupled with the free magnet and coupled between a pair of interconnect line segments. The second electrode and the pair of interconnect line segments include a spin orbit torque material. The second electrode has a conductive path cross-section that is smaller than a cross section of the conductive path in at least one of the interconnect line segments.
1. A spin orbit torque (SOT) device, comprising:
a tunnel barrier between a free magnet and a fixed magnet;
a first electrode coupled with the fixed magnet; and
a second electrode coupled with the free magnet and directly coupled between a pair of interconnect line segments, wherein:
the second electrode and the pair of interconnect line segments each comprise a spin orbit torque material; and
a conductive path has a cross-section within the second electrode that is smaller than a cross-section within at least one of the interconnect line segments.
2. The SOT device of claim 1 , wherein the cross-section of the conductive path within the second electrode is smaller than a cross-section within either of the pair of interconnect line segments.
3. The SOT device of claim 1 , wherein the second electrode has a first thickness that is less than a second thickness of at least one of the interconnect line segments.
4. The SOT device of claim 3 , wherein the second electrode comprises the first thickness of the spin orbit coupling material, and at least one of the interconnect line segments comprises a second thickness of the spin orbit coupling material.
5. The SOT device of claim 4 , wherein a bottom of the second electrode and a bottom of the interconnect line segments are co-planar if the free magnet is below the second electrode, and a top of the second electrode and a top of the interconnect line segments are co-planar if the free magnet is above the second electrode.
6. The SOT device of claim 3 wherein at least one of the interconnect line segments comprises the first thickness of the spin orbit coupling material, and a second material on the spin orbit coupling material.
7. The SOT device of claim 6 , wherein the second material is on top of the spin orbit coupling material if the free magnet is below the second electrode, and is below the spin orbit torque material if the free magnet is above the second electrode.
8. The SOT device of claim 3 , wherein both the second electrode and at least one of the interconnect line segments comprise a first width of the spin orbit coupling material.
9. The SOT device of claim 1 , wherein at least a portion of the second electrode has a first width, and at least one of the interconnect line segments has a second width, greater than the first width.
10. The SOT device of claim 1 , wherein the second electrode separates the pair of interconnect line segments by a distance at least equal to a diameter or a length of the free magnet.
11. The SOT device of claim 10 , wherein the distance is not more than 20% greater than the diameter or the length of the free magnet.
12. The SOT device of claim 1 , wherein at least one of the pair of interconnect lines segments has a length at least equal to a diameter or a length of the free magnet.
13. An apparatus, comprising:
a transistor above a substrate, the transistor comprising:
a drain contact coupled to a drain;
a source contact coupled to a source; and
a gate contact coupled to a gate;
a spin orbit torque (SOT) device coupled with the drain contact, the SOT device comprising:
a free magnet;
a fixed magnet;
a tunnel barrier between the free magnet and the fixed magnet;
a first electrode coupled with the fixed magnet; and
a second electrode coupled with the free magnet and coupled between a first interconnect line segment and a second interconnect line segment, wherein:
the second electrode, the first interconnect line segment, and the second interconnect line segment comprise a spin orbit torque material; and
a cross-section of a conductive path in the second electrode is smaller than a cross-section of a conductive path in at least one of the first or the second interconnect line segments;
a first contact over and coupled with the first interconnect line segment; and
a second contact over and coupled with a second interconnect line segment.
14. The apparatus of claim 13 , wherein the apparatus is coupled to a power supply.