Granted Patent B2

US 8,758,850 · App. 13/238,972 · Granted Jun 24, 2014

Abstract

Claims (33)

1. A method of manufacturing a spin transfer torque magnetic random access memory (STTMRAM) magnetic tunnel junction film stack comprising:

a) first depositing a magnetic interface layer on top of a barrier layer to form a magnetic tunnel junction (MTJ), the magnetic interface layer being made partially of boron (B)

b) after the first depositing step, annealing the STTMRAM MTJ film stack at a first temperature after depositing the magnetic interface layer, the annealing being in-situ within a deposition system without breaking the vacuum thereby avoiding oxidization and contamination of the surface of the magnetic interface layer;

c) after the annealing step, cooling down the STTMRAM MTJ film stack to a second temperature that is lower than the first temperature; and

d) after the cooling down step, second depositing a top layer on top of the magnetic interface layer, wherein the top layer is made of a single layer or has a multi-layer structure necessary to make the MTJ stack function in the STTMRAM MTJ film stack,

wherein the top layer comprises at least one magnetic sub-layer.

2. A method of manufacturing, as recited in claim 1 , further including the step of second annealing after depositing the top layers, using a third temperature that is higher than the second temperature.

3. A method of manufacturing, as recited in claim 1 , wherein the top layer is made of any one or a combination of the following material: Co, Fe, B, Pd, Pt, Ta, Ru, Tb, Cr, Mg, O, Cu, Zn, or Hf.

4. A method of manufacturing, as recited in claim 1 , wherein the top layer is made of interlaced magnetic and non-magnetic layers.

5. A method of manufacturing, as recited in claim 1 , wherein the magnetic interface layer being is further made of any combination of the following material: Co, Fe, Ta, Ti, Ni, Cr, Pt, Pd, Tb, Zn, O, Cu or Zr.

6. A method of manufacturing, as recited in claim 1 , wherein the magnetic interface layer is composed of a multilayer structure with magnetic layer and non-magnetic layer where at least one magnetic layer interfaces the barrier layer.

7. A method of manufacturing, as recited in claim 6 , wherein the multilayer structure includes a top surface layer.

8. A method of manufacturing, as recited in claim 7 , wherein the top surface layer is made of non-magnetic material.

9. A method of manufacturing, as recited in claim 7 , wherein the top surface layer is made of a material comprising any of the materials: Ta, Pd, Ru, Mg, O, Hf, Tb, Pt, Ti, Cu, or Hf.

10. A method of manufacturing, as recited in claim 1 , wherein the magnetic interface layer has a perpendicular magnetization relative to a film plane.

11. A method of manufacturing, as recited in claim 1 , wherein the magnetic interface layer has an in-plane magnetization relative to a film plane.

12. A method of manufacturing, as recited in claim 1 , wherein the second within-film magnetic exchange is greater than the first within-film magnetic exchange.

13. A method of manufacturing, as recited in claim 1 , further including a bottom magnetic layer on top of which the barrier layer is formed.

14. A method of manufacturing, as recited in claim 13 , wherein the bottom magnetic layer has a perpendicular magnetization relative to a film plane.

15. A method of manufacturing, as recited in claim 13 , wherein the bottom magnetic layer has an in-plane magnetization relative to a film plane.

16. A method of manufacturing a magneto-resistive film stack comprising:

a) first depositing a magnetic interface layer on top of a magneto-resistive junction layer to form a magneto-resistive junction;

b) after the first depositing step, annealing the magneto-resistive junction film stack at a first temperature after depositing the magnetic interface layer, the annealing being in-situ within a deposition system without breaking the vacuum thereby avoiding oxidization and contamination of the surface of the magnetic interface layer;

c) after the annealing step, cooling down the magneto-resistive junction film stack to a second temperature that is lower than the first temperature; and

d) after the cooling down step, second depositing a top layer on top of the magnetic interface layer,

wherein the top layer is made of a single layer or has a multi-layer structure that are necessary to make magneto-resistive junction function.

17. A method of manufacturing, as recited in claim 16 , wherein the second within-film magnetic exchange is greater than the first within-film magnetic exchange.

18. A method of manufacturing, as recited in claim 16 , wherein the magneto-resistive junction layer is a metallic layer.

19. A method of manufacturing, as recited in claim 18 , wherein the magneto-resistive junction layer comprises the materials: Cu, Ag, or Au.

20. A method of manufacturing, as recited in claim 16 , wherein the magneto-resistive junction layer is a magnetic tunneling barrier.

21. A method of manufacturing, as recited in claim 20 , wherein the magneto-resistive junction layer comprises an oxide of any of the materials: Mg, Al, Zn, or Ti.

22. A method of manufacturing, as recited in claim 16 , wherein the magneto-resistive junction layer is formed of metallic pillars dispersed in a non-metallic matrix.

23. A method of manufacturing, as recited in claim 22 , wherein the metallic pillars are made of materials comprising: Cu, Ag, or Au, and the non-metallic matrix is an oxide layer of Mg, Al, Zn, or Ti.

Assignments (6)