MTJ structures including magnetism induction pattern and magnetoresistive random access memory devices including the same
A magnetic tunnel junction (MTJ) structure includes a fixed layer pattern structure having a perpendicular magnetization direction, a tunnel barrier pattern on the fixed layer pattern structure, a free layer pattern on the tunnel barrier pattern, the free layer pattern having a perpendicular magnetization direction, a first surface magnetism induction pattern on the free layer pattern, the first surface magnetism induction pattern inducing a perpendicular magnetism in a surface of the free layer pattern, a conductive pattern on the first surface magnetism induction pattern, and a ferromagnetic pattern on the conductive pattern.
1. A magnetic tunnel junction (MTJ) structure, comprising:
a fixed layer pattern structure having a perpendicular magnetization direction;
a tunnel barrier pattern on the fixed layer pattern structure;
a free layer pattern on the tunnel barrier pattern, the free layer pattern having a perpendicular magnetization direction;
a first surface magnetism induction pattern on the free layer pattern, the first surface magnetism induction pattern inducing a perpendicular magnetism in a surface of the free layer pattern;
a conductive pattern on the first surface magnetism induction pattern;
a ferromagnetic pattern on the conductive pattern, and
a second surface magnetism induction pattern between the conductive pattern and the ferromagnetic pattern, wherein the second surface magnetism induction pattern includes magnesium oxide (MgO).
2. The MTJ structure as claimed in claim 1 , wherein the ferromagnetic pattern has a perpendicular magnetization direction.
3. The MTJ structure as claimed in claim 2 , wherein the second surface magnetism induction pattern induces a perpendicular magnetism in a surface of the ferromagnetic pattern.
4. The MTJ structure as claimed in claim 3 , wherein the second surface magnetism induction pattern has a thickness less than that of the tunnel barrier pattern.
5. The MTJ structure as claimed in claim 1 , wherein the ferromagnetic pattern has an in-plane magnetization direction.
6. The MTJ structure as claimed in claim 1 , wherein the ferromagnetic pattern includes a resonance layer.
7. The MTJ structure as claimed in claim 1 , wherein the first surface magnetism induction pattern includes magnesium oxide (MgO).
8. The MTJ structure as claimed in claim 1 , wherein the first surface magnetism induction pattern has a thickness that is less than that of the tunnel barrier pattern.
9. The MTJ structure as claimed in claim 8 , wherein the thickness of the first surface magnetism induction pattern is equal to or less than half of the thickness of the tunnel barrier pattern.
10. The MTJ structure as claimed in claim 1 , wherein the tunnel barrier pattern includes magnesium oxide (MgO) or aluminum oxide (AlOx).
11. The MTJ structure as claimed in claim 1 , wherein the ferromagnetic pattern includes at least one of iron, nickel, and cobalt.
12. The MTJ structure as claimed in claim 1 , wherein the conductive pattern includes a metal.
13. The MTJ structure as claimed in claim 12 , wherein the conductive pattern includes at least one of copper, aluminum and tungsten.