Magnetic memory cell and method of manufacturing the same
The present invention suppresses short circuits of a magnetic memory cell and a deterioration of the characteristics of a magnetic layer. A magnetic memory cell includes: a data storage layer; a tunnel barrier layer formed on the data storage layer; a reference layer formed on the tunnel barrier layer so as to cover a part of the tunnel barrier layer; and a metallic oxide layer formed on the tunnel barrier layer without covering the reference layer. The metallic oxide layer contains an oxide of a material of a contact part of the reference layer with the tunnel barrier layer.
1. A magnetic memory cell comprising:
a fixed magnetization layer;
a first magnetic layer including a fixed magnetization area formed on a surface of the fixed magnetization layer and having a magnetization which is fixed in the same direction as the fixed magnetization layer;
a tunnel barrier layer formed over the first magnetic layer;
a second magnetic layer formed over the tunnel barrier layer so as to partially cover the tunnel barrier layer, the second magnetic layer comprising a magnetic layer and a first non-magnetic layer; and
a metallic oxide layer formed on an upper surface of the tunnel barrier layer such that the tunnel barrier layer is formed between the metallic oxide layer and the fixed magnetization layer, the metallic oxide layer including an oxidized part of the magnetic layer and the first non-magnetic layer.
2. The magnetic memory cell according to claim 1 , wherein the tunnel barrier layer comprises a MgO layer,
wherein the magnetic layer of the second magnetic layer includes a CoFeB layer formed over the tunnel barrier layer,
wherein the first non-magnetic layer comprises an intermediate layer formed over the CoFeB layer,
wherein the second magnetic layer further comprises a perpendicularly magnetized layer that is formed over the intermediate layer and exhibits perpendicular magnetic anisotropy, and
wherein the metallic oxide layer comprises an oxide obtained by oxidizing CoFeB and an oxide obtained by oxidizing the intermediate layer.
3. The magnetic memory cell according to claim 1 , wherein the metallic oxide layer has a thickness greater than 1.0 nm.
4. The magnetic memory cell according to claim 2 , wherein the intermediate layer comprises a Ta film.
5. The magnetic memory cell according to claim 2 , wherein the metallic oxide layer includes no oxide of a material of the perpendicularly magnetized layer.
6. A magnetic random access memory comprising the magnetic memory cell according to claim 1 .
7. The magnetic memory cell according to claim 1 , wherein the first magnetic layer comprises a data storage layer which stores data as a direction of magnetization.
8. The magnetic memory cell according to claim 1 ,
wherein the first magnetic layer further comprises:
a reversible magnetization area formed outside the surface of the fixed magnetization layer.
9. The magnetic memory cell according to claim 8 , wherein the second magnetic layer is formed over the reversible magnetization area of the first magnetic layer.
10. The magnetic memory cell according to claim 1 , wherein the second magnetic layer further comprises:
a first perpendicularly magnetized layer formed on the first non-magnetic layer and exhibiting perpendicular magnetic anisotropy;
a second non-magnetic layer formed on the first perpendicularly magnetized layer; and
a second perpendicularly magnetized layer formed on the second non-magnetic layer.
11. A magnetic memory cell comprising:
a fixed magnetization layer;
a first magnetic layer including a fixed magnetization area formed on a surface of the fixed magnetization layer and having a magnetization which is fixed in the same direction as the fixed magnetization layer;
a tunnel barrier layer formed on the first magnetic layer;
a second magnetic layer formed on a surface of the tunnel barrier layer, the second magnetic layer comprising a magnetic layer and a non-magnetic metal layer; and
a metallic oxide layer formed on the surface of the tunnel barrier layer and on opposing sides of the magnetic layer and the non-magnetic metal layer such that the tunnel barrier layer is formed between the metallic oxide layer and the fixed magnetization layer, the metallic oxide layer including an oxidized part of the magnetic layer and the non-magnetic metal layer.