Granted Patent B2

US 8,623,452 · App. 12/965,733 · Granted Jan 7, 2014

Abstract

Claims (29)

1. A method of manufacturing a spin transfer torque magnetic random access memory (STTMRAM) element comprising:

first depositing a first free sub-layer on top of a barrier layer to form a magnetic tunnel junction (MTJ), the first free sub-layer being made partially of boron (B) and having a first within-film magnetic exchange;

after the first depositing step, annealing the STTMRAM element at a first temperature after depositing the first free sub-layer, the annealing causing a second free sub-layer to be formed on top of the first free sub-layer

after the annealing step, cooling down the STTMRAM element to a second temperature that is lower than the first temperature; and

after the cooling down step, second depositing a third free sub-layer directly on top the second free sub-layer, the first, second, and third free sub-layers forming a free layer,

wherein the third free sub-layer having a second within-film magnetic exchange, the second within-film magnetic exchange being different than the first within-film magnetic exchange, the amount of B in the third sub-free layer being less than the amount of B in the second free layer.

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

3. A method of manufacturing, as recited in claim 2 , further including the step of depositing additional layers on top of the third free sub-layer.

4. A method of manufacturing, as recited in claim 1 , wherein the third free layer is made of cobolt-iron (CoFe).

5. A method of manufacturing, as recited in claim 1 , wherein the first temperature is approximately more than or equal to 200 degrees Celsius (° C.) and less than or equal to 500° C.

6. A method of manufacturing, as recited in claim 1 , wherein the first free sub-layer comprises: Co, Fe, Ni, B, Ta, Ti, Cu, Zr, Cr or Pt.

7. 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.

8. A method of manufacturing, as recited in claim 1 , wherein the annealing step reduces the B content at an interface between the first free sub-layer and wherein the barrier layer, the second free sub-layer being made partially of B, the amount of B in the second free sub-layer being greater than the amount of B in the first free sub-layer.

9. The method of manufacturing, as recited in claim 1 , wherein each of the first, second, and third free sub-layers have a magnetization associated therewith and further wherein, the magnetization of each of the first, second, and third free sub-layers is switchable.

10. The method of manufacturing, as recited in claim 1 , wherein the third free sub-layer is made partially of boron (B).

11. The method of manufacturing, as recited in claim 1 , wherein the first, second, and the third free sub-layers are each magnetic.

12. A method of manufacturing a spin toque transfer magnetic random access memory (STTMRAM) element comprising:

first depositing a first free sub-layer on top of a barrier layer to form a magnetic tunnel junction (MTJ), the first free sub-layer being made partially of boron (B), the first free sub-layer having a first within-film magnetic exchange;

after the first depositing step, annealing the STTMRAM element at a first temperature; the annealing causing a second free sub-layer to be formed on top of the first free sub-layer

after the annealing step, cooling down the STTMRAM element to a second temperature that is lower than the first temperature; and

after the cooling down step, second depositing a third free sub-layer directly on top of the second free sub-layer with the third free sub-layer being substantially void of B and having a second within-film magnetic exchange, the first, second, and third free sub-layers forming a free layer,

wherein the second within-film magnetic exchange is different than the first within-film magnetic exchange.

13. A method of manufacturing, as recited in claim 12 , further including the step of second annealing after depositing the third free sub-layer, using a third temperature that is lower than the first temperature and higher than the second temperature.

14. .A method of manufacturing, as recited in claim 13 , further including the step of depositing additional layers on top of the third free sub-layer.

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

16. A method of manufacturing, as recited in claim 12 , wherein the annealing step reduces the B content at an interface between the first free sub-layer and the barrier layer, and wherein the second free sub-layer being made partially of B, the amount of B in the second free sub-layer being greater than the amount of B in the first free sub-layer.

17. The method of manufacturing, as recited in claim 12 , wherein each of the first, second, and third free sub-layers have a magnetization associated therewith and further wherein, the magnetization of each of the first, second, and third free sub-layers is switchable.

18. The method of manufacturing, as recited in claim 12 , wherein the third free sub-layer is made partially of boron (B).

19. The method of manufacturing, as recited in claim 12 , wherein the first, second, and the third free sub-layers are each magnetic.

Assignments (6)