CLAIMS
What is claimed is:
1. A material layer stack for a pSTTM device, the material layer stack comprising:
a magnetic tunnel junction (MTJ) including a fixed magnetic layer, a tunnel barrier
disposed above the fixed magnetic layer and a free magnetic layer disposed on the tunnel barrier;
an oxide layer disposed on the free magnetic layer;
a protective layer disposed on the oxide layer; and
a conductive capping layer disposed directly on the protective layer, the conductive capping layer having a low oxygen affinity.
2. The material layer stack of claim 1, wherein the conductive capping layer is selected from the group consisting of molybdenum and ruthenium.
3. The material layer stack of claim 1, wherein the conductive capping layer includes a metal that has an oxygen affinity that is less than the oxygen affinity of tantalum.
4. The material layer stack of claim 1, wherein the conductive capping layer is selected from a highly siderophile group of elements consisting of osmium, iridium, platinum, rhenium and gold.
5. The material layer stack of claim 1, wherein the conductive capping layer has a thickness between 1.5nm - 5.0nm.
6. The material layer stack of claim 1, wherein the protective layer comprises cobalt and iron.
7. The material layer stack of claim 6, wherein the protective layer further comprises boron.
8. The material layer stack of claim 1, wherein the protective layer has a thickness between 0.3 nm-1.5nm.
9. The material layer stack of claim 1, wherein the protective layer is not magnetic.
10. The material layer stack of claim 1, wherein the oxide layer is approximately 10-1000 times more conductive than the tunnel barrier.
11. The material layer stack of claim 1 , wherein the oxide layer has a thickness between 0.3nm-1.5nm.
12. A material layer stack for a pSTTM device, the material layer stack comprising:
a magnetic tunnel junction (MTJ), the MTJ comprising:
a fixed magnetic layer;
a tunnel barrier disposed above the fixed magnetic layer;
a first free magnetic layer disposed on the tunnel barrier;
a coupling layer disposed above the first free magnetic layer;
a second free magnetic layer disposed on the coupling layer;
a oxide layer disposed on the second free magnetic layer;
a protective layer disposed on the oxide layer;
a conductive capping layer disposed directly on the protective layer, the conductive capping layer having a low oxygen affinity;
a bottom electrode layer disposed below the MTJ; and
a top electrode layer disposed above the capping layer.
13. The material layer stack of claim 12, wherein the conductive capping layer is selected from the group consisting of molybdenum, ruthenium.
14. The material layer stack of claim 12, wherein the conductive capping layer has a thickness between 1.5nm - 5.0nm.
15. The material layer stack of claim 12, wherein the protective layer comprises cobalt, boron and iron.
16. The material layer stack of claim 12, wherein the protective layer has a thickness between 0.3nm-1.5nm
17. The material layer stack of claim 12, wherein the oxide layer has a thickness that is less than the thickness of the tunnel barrier.
18. The material layer stack of claim 12, wherein the top electrode is a material different from the material of the capping layer.
19. The material layer stack of claim 12, wherein a synthetic antiferromagnetic layer is disposed between the fixed layer and the bottom electrode layer.
20. A method comprising, fabricating a material layer stack for a non-volatile memory device, the method comprising:
forming a bottom electrode layer;
forming a magnetic tunnel junction (MTJ) above the bottom electrode, the forming comprising:
forming a fixed magnetic layer;
forming a tunnel barrier on fixed magnetic layer;
forming a storage layer above the tunnel barrier;
forming an oxide layer on the coupling layer;
forming a protective layer on the oxide layer;
forming a conductive capping layer on the protective layer; and
forming a top electrode layer on the conductive capping layer.
21 The method of claim 20, wherein forming the protective layer includes depositing with materials that have a mass number less than the mass number of the capping layer.
22. The method of claim 20, wherein forming the capping layer includes depositing with a material that has an oxygen affinity of less than the oxygen affinity of tantalum
23. The method of claim 20, wherein forming the capping layer includes intermixing between materials between materials comprising the capping layer and the materials comprising the protective layer.