Granted Patent B2

US 12,745,571 · App. 18/435,084 · Granted Sep 22, 2026

Inventors: Jian-Ping Wang (Shoreview, MN); Deyuan Lyu (Minneapolis, MN); Daniel B. Gopman (Gaithersburg, MD); Jenae E. Shoup (La Jolla, CA)

Assignee: Regents of the University of Minnesota

H10N50/85H10B61/20H10N50/01H10N50/10

Abstract

Claims (37)

1 . A device, comprising:

a silicon wafer substrate;

a seed layer formed on a surface of the silicon wafer substrate, wherein the seed layer comprises at least one of magnesium oxide (MgO) or strontium titanate (SrTiO 3 ) having an (001) texture; and

a perpendicular magnetic anisotropy (PMA) structure exhibiting crystalline PMA formed on the seed layer, wherein the PMA structure comprises at least one of iron-palladium (FePd) alloy, iron-platinum alloy (FePt), or iron-platinum-palladium alloy (Fe(Pt x Pd (1-x) )).

2 . The device of claim 1 , wherein the device comprises at least a portion of a memory device or a logic device.

3 . The device of claim 1 , wherein the device comprises a magnetic tunnel junction (MTJ), and wherein the PMA structure is a free layer.

4 . The device of claim 1 , wherein the silicon wafer comprises both elemental silicon (Si) and silicon dioxide (SiO 2 ).

5 . The device of claim 1 , wherein the surface of the silicon wafer substrate is an amorphous SiO 2 surface.

6 . The device of claim 5 , wherein the surface of the silicon wafer substrate defines one or more metallized contacts, and the one or more metallized contacts comprise copper, aluminum, tungsten, or other metals.

7 . The device of claim 1 , wherein the seed layer is polycrystalline.

8 . The device of claim 1 , wherein the seed layer is a thin film having a thickness measured normal to the surface of the silicon wafer substrate of from about 0.5 nanometers to about 20 nanometers.

9 . The device of claim 1 , wherein the PMA structure defines an L1 0 -phase structure.

10 . The device of claim 1 , further comprising at least one bridge layer between the seed layer and the PMA structure.

11 . The device of claim 10 , wherein the at least one bridge layer comprises two bridge layers including a first bridge layer and a second bridge layer.

12 . The device of claim 11 , wherein the first bridge layer comprises chromium and the second bridge layer comprises platinum.

13 . The device of claim 12 , wherein the first bridge layer and the second bridge layer each define a respective thickness measured normal to the surface of the silicon wafer substrate,

wherein the thickness of the first bridge layer is from about 8 nanometers to about 30 nanometers, and

wherein the thickness of the second bridge layer is from about 1 nanometer to about 10 nanometers.

14 . The device of claim 1 , wherein the PMA structure defines a thickness measured normal to the surface of the silicon wafer substrate, wherein the thickness is from about 2 nanometers to about 15 nanometers.

15 . The device of claim 1 , wherein the PMA structure is formed with a plurality of sub-layers that form a synthetic antiferromagnetic (SAF) structure.

16 . The device of claim 15 , wherein the sub-layers include three sub-layers, wherein two of the three sub-layers comprise FePd.

17 . The device of claim 16 , wherein one of the three sub-layers comprises one or more of iridium (Ir), ruthenium (Ru), rhodium (Rh), chromium (Cr), rhenium (Re), osmium (Os), molybdenum (Mo), or combinations thereof.

18 . A spin-orbit torque (SOT) MRAM device or a logic device comprising:

a silicon wafer substrate;

a seed layer formed on a surface of the silicon wafer substrate;

a perpendicular magnetic anisotropy (PMA) structure exhibiting crystalline PMA formed on the seed layer, wherein the PMA structure defines an L1 0 -phase structure and comprises at least one of iron-palladium alloy (FePd), iron-platinum alloy (FePt), or iron-platinum-palladium alloy (Fe(Pt x Pd (1-x) ));

a magnetic tunnel junction bridge layer including a MgO tunnel barrier;

a hard perpendicular magnetic anisotropy (PMA) structure exhibiting PMA formed on the MgO tunnel barrier with a pinned magnetization orientation; and

a conducting layer formed on the hard PMA structure, wherein a current delivered through the conducting layer, hard PMA structure, and the PMA structure sets a magnetization state of the PMA structure.

19 . A device, comprising:

a silicon wafer substrate with pre-patterned transistor structures and metal layers including a top metal layer;

a seed layer formed on a surface of the top metal layer;

a bridge layer formed on a surface of the seed layer; and

a perpendicular magnetic anisotropy (PMA) structure exhibiting crystalline PMA formed on the bridge layer, wherein the PMA structure comprises at least one of iron-palladium (FePd) alloy, iron-platinum alloy (FePt), or iron-platinum-palladium alloy (Fe(Pt x Pd (1-x) )).

20 . A method, comprising:

forming a seed layer on a surface of a silicon wafer substrate; and

forming a perpendicular magnetic anisotropy (PMA) structure exhibiting crystalline PMA on the seed layer, wherein forming the PMA structure comprises forming a plurality of sub-layers that together form a synthetic antiferromagnetic (SAF) structure, and wherein the PMA structure comprises at least one of iron-palladium (FePd) alloy, iron-platinum alloy (FePt), or iron-platinum-palladium alloy (Fe(Pt x Pd (1-x) )).

Assignments (3)

Continuity (2)

References Cited (177)