Magnetic device and magnetic random access memory

1. A spin-orbit-torque (SOT) magnetic device, comprising:

a bottom metal layer;

a first magnetic layer disposed over the bottom metal layer;

a spacer layer disposed over the first magnetic layer;

a second magnetic layer disposed over the spacer layer; and

a diffusion barrier layer disposed between the bottom metal layer and the first magnetic layer,

wherein the diffusion barrier layer includes at least one of iron or cobalt, and suppresses an element of the first magnetic layer from diffusing into the bottom metal layer.

2. The SOT magnetic device of claim 1 , wherein the first magnetic layer includes iron and cobalt.

3. The SOT magnetic device of claim 2 , wherein:

the diffusion barrier layer includes iron, and

an atomic percentage of iron in the diffusion barrier layer is higher than an atomic percentage of iron in the first magnetic layer.

4. The SOT magnetic device of claim 3 , wherein the first magnetic layer and the diffusion barrier layer further include boron.

5. The SOT magnetic device of claim 4 , wherein an atomic percentage of the boron in the diffusion barrier layer is higher than an atomic percentage of the boron in the first magnetic layer.

6. The SOT magnetic device of claim 2 , wherein:

the first magnetic layer is Fe x Co y B 1-x-y , and

the diffusion barrier layer is Fe z B 1-z , where z>x.

7. The SOT magnetic device of claim 6 , wherein 0.50≤x≤0.70 and 0.65≤z≤0.90.

8. The SOT magnetic device of claim 2 , wherein:

the diffusion barrier layer includes cobalt, and

an atomic percentage of cobalt in the diffusion barrier layer is higher than an atomic percentage of cobalt in the first magnetic layer.

9. The SOT magnetic device of claim 1 , wherein a thickness of the diffusion barrier layer is in a range from 0.1 nm to 0.6 nm.

10. The SOT magnetic device of claim 1 , further comprising an intermediate metal layer disposed between the spacer layer and the second magnetic layer.

11. The SOT magnetic device of claim 10 , wherein the intermediate metal layer is made of magnesium and the spacer layer is made of magnesium oxide.

12. The SOT magnetic device of claim 1 , further comprising a top metal layer disposed over the second magnetic layer.

13. The SOT magnetic device of claim 12 , wherein the top metal layer is made of ruthenium.

14. The SOT magnetic device of claim 1 , wherein the second magnetic layer includes iron, cobalt and boron.

15. A spin-orbit-torque (SOT) magnetic device, comprising:

a bottom metal layer;

a first magnetic layer disposed over the bottom metal layer;

a spacer layer disposed over the first magnetic layer;

a second magnetic layer disposed over the spacer layer; and

a diffusion barrier layer disposed between a magnetic dead layer and the first magnetic layer, wherein:

the magnetic dead layer is disposed between the bottom metal layer and the first magnetic layer, and

the diffusion barrier layer suppresses an element of the first magnetic layer from diffusing into the bottom metal layer.

16. The SOT magnetic device of claim 15 , wherein:

the first magnetic layer is Fe x Co y B 1-x-y , and

the diffusion barrier layer is Fe z B 1-z , where z>x.

17. A spin-orbit-torque (SOT) magnetic device, comprising:

a bottom metal layer;

a first magnetic layer disposed over the bottom metal layer;

a spacer layer disposed over the first magnetic layer;

a second magnetic layer disposed over the spacer layer; and

a diffusion barrier layer disposed between the bottom metal layer and the first magnetic layer,

wherein the diffusion barrier layer includes at least one of boron, magnesium or tantalum.

18. The SOT magnetic device of claim 17 , wherein the diffusion barrier layer is made of magnesium.

19. The SOT magnetic device of claim 17 , wherein the diffusion barrier layer is made of an oxide of tantalum.

20. The SOT magnetic device of claim 17 , wherein the bottom metal layer is made of tantalum.