MnN and Heusler layers in magnetic tunnel junctions
Materials are disclosed that are used as seed layers in the formation of MRAM elements. In particular, a MnN layer oriented in the (001) direction is grown over a substrate. A magnetic layer overlying and in contact with the MnN layer forms part of a magnetic tunnel junction, in which the magnetic layer includes a Heusler compound that includes Mn. The magnetic tunnel junction includes the magnetic layer, a tunnel barrier overlying the magnetic layer, and a first (magnetic) electrode overlying the tunnel barrier. A second electrode is in contact with the MnN layer.
1. A stacked structure, comprising:
a substrate;
a MnN layer overlying the substrate, wherein the MnN layer is predominantly oriented in the (001) direction; and
a magnetic layer overlying and in contact with the MnN layer, the magnetic layer forming part of a magnetic tunnel junction, wherein the magnetic layer includes a Heusler compound that includes Mn, and wherein the magnetic layer is ferromagnetic or ferrimagnetic.
2. The structure of claim 1 , wherein the Heusler compound is tetragonal.
3. The structure of claim 1 , wherein the magnetic layer and the magnetic tunnel junction have respective crystalline structures that are coincident with each other.
4. The structure of claim 1 , wherein the MnN layer and the magnetic layer have respective crystalline structures that are coincident with each other.
5. The structure of claim 1 , wherein the magnetic tunnel junction includes:
the magnetic layer;
a tunnel barrier overlying the magnetic layer; and
a first electrode overlying the tunnel barrier, wherein the first electrode is made of magnetic material.
6. The structure of claim 5 , comprising;
a capping layer overlying and in contact with the magnetic tunnel junction.
7. The structure of claim 6 , wherein the tunnel barrier is MgO.
8. The structure of claim 6 , wherein the tunnel barrier is Mg 1-x Al 2-x O 4 , wherein −0.5<x<0.5.
9. The structure of claim 6 , wherein the tunnel barrier is AlN.
10. The structure of claim 6 , comprising:
a second electrode in contact with the MnN layer.
11. An array, comprising:
at least 100 stacked structures given by claim 10 , said structures being interconnected to form a memory device.
12. A method, comprising:
writing data into the first electrodes of the array of claim 11 .
13. The method of claim 12 , comprising:
reading data stored in the first electrodes of the array.
14. A stacked structure, comprising:
a substrate;
a MnN layer overlying the substrate, wherein the MnN layer is predominantly oriented in the (001) direction; and
a magnetic layer overlying and in contact with the MnN layer, wherein the magnetic layer includes a Heusler compound that includes Mn, and wherein the magnetic layer is ferromagnetic or ferrimagnetic.
15. The stacked structure of claim 14 , wherein the magnetic layer includes discrete magnetic domains.
16. The stacked structure of claim 15 , wherein the discrete magnetic domains have respective magnetization directions that correspond to data that have been stored in the stacked structure.