Magnetic tunneling junction device and memory device including the same
Provided are a magnetic tunneling junction device having more stable perpendicular magnetic anisotropy (PMA) and/or increased operating speed, and/or a memory device including the magnetic tunneling junction device. The magnetic tunneling junction device includes a free layer having a first surface and a second surface opposite the first surface; a pinned layer facing the first surface of the free layer; a first oxide layer between the pinned layer and the free layer; and a second oxide layer on the second surface of the free layer. The free layer includes a magnetic material X doped with a non-magnetic metal. The second oxide layer includes ZO x which is an oxide of a metal Z. An oxygen affinity of the metal Z is greater than an oxygen affinity of the non-magnetic metal X.
1 . A magnetic tunneling junction device comprising:
a free layer having a first surface and a second surface opposite the first surface;
a pinned layer facing the first surface of the free layer;
a first oxide layer between the pinned layer and the free layer; and
a second oxide layer on the second surface of the free layer,
wherein
the free layer comprises a magnetic material doped with a non-magnetic metal,
the second oxide layer comprises a metal oxide, and
a metal in the metal oxide of the second oxide layer is different from the non-magnetic metal of the free layer.
2 . The magnetic tunneling junction device of claim 1 , wherein
the magnetic material of the free layer comprises at least one of Fe, Co, Ni, Mn, a Fe-containing alloy, a Co-containing alloy, a Ni-containing alloy, a Mn-containing alloy and a Heusler alloy, and
wherein the non-magnetic metal of the free layer comprises at least one of Ru, Ir, Ti, Zn, Ga, Al, Sn, W, Sb, V, Cr, Ge, Si, Tb, Sc, Y, Rh, In, Ca, Sr, Ba, Be, V, Li, Cd, and Pb.
3 . The magnetic tunneling junction device of claim 2 , wherein
the metal in the metal oxide of the second oxide layer comprises at least one metal element having a first oxygen affinity greater than a second oxygen affinity of the non-magnetic metal of the free layer, and
the at least one metal element being at least one of Mg, B, Fe, Co, Ni, Ru, Ir, Ti, Zn, Ga, Ta, Al, Mo, Zr, Sn, W, Sb, V, Nb, Cr, Ge, Si, Hf, Tb, Sc, Y, Ru, Rh, and In.
4 . The magnetic tunneling junction device of claim 1 , wherein
the non-magnetic metal of the free layer comprises at least one metal element selected from Ru, Ir, Zn, Ga, Sn, W, Sb, V, Cr, Ge, Rh, and In, and
the metal in the metal oxide of the second oxide layer comprises at least one metal element selected from Ti, Ta, Al, Zr, Si, Hf, Tb, Sc, and Y.
5 . The magnetic tunneling junction device of claim 1 , wherein
a doping concentration of the non-magnetic metal in the free layer is in a range of about 5 at % to about 50 at %.
6 . The magnetic tunneling junction device of claim 1 , wherein
the free layer further comprises boron (B), and
a boron concentration of the free layer is in a range of about 5 at % to about 50 at %.
7 . The magnetic tunneling junction device of claim 6 , wherein
the second oxide layer further comprises boron absorbed from the free layer.
8 . The magnetic tunneling junction device of claim 1 , wherein
the first oxide layer comprises a metal oxide having a stoichiometrically oxygen-deficient composition.
9 . The magnetic tunneling junction device of claim 8 , wherein
the first oxide layer comprises a first region adjacent to the pinned layer, and a second region adjacent to the free layer, and
a first proportion of oxygen or nitrogen in the second region is greater than a second proportion of a respective one of oxygen or nitrogen in the first region.
10 . The magnetic tunneling junction device of claim 9 , wherein
the first oxide layer further comprises a metal layer between the first region and the second region.
11 . The magnetic tunneling junction device of claim 1 , wherein
the second oxide layer comprises a metal oxide having a stoichiometrically oxygen-deficient composition.
12 . A magnetic tunneling junction device comprising:
a free layer having a first surface and a second surface opposite the first surface;
a pinned layer facing the first surface of the free layer;
a first oxide layer between the pinned layer and the free layer;
a second oxide layer on the second surface of the free layer; and
a capping metal layer in contact with the second oxide layer,
wherein
the free layer comprises a magnetic material doped with a non-magnetic metal, and
the capping metal layer comprises a metal different from the non-magnetic metal of the free layer.
13 . The magnetic tunneling junction device of claim 12 , wherein
the magnetic material of the free layer comprises at least one of Fe, Co, Ni, Mn, a Fe-containing alloy, a Co-containing alloy, a Ni-containing alloy, a Mn-containing alloy and a Heusler alloy, and
the non-magnetic metal of the free layer comprises at least one of Ru, Ir, Ti, Zn, Ga, Al, Sn, W, Sb, V, Cr, Ge, Si, Tb, Sc, Y, Rh, In, Ca, Sr, Ba, Be, V, Li, Cd, and Pb.
14 . The magnetic tunneling junction device of claim 13 , wherein
the metal of the capping metal layer comprises at least one metal element having a first oxygen affinity greater than a second oxygen affinity of the non-magnetic metal of the free layer, and
the at least one metal element is selected from Mg, B, Fe, Co, Ni, Ru, Ir, Ti, Zn, Ga, Ta, Al, Mo, Zr, Sn, W, Sb, V, Nb, Cr, Ge, Si, Hf, Tb, Sc, Y, Ru, Rh, and In.
15 . The magnetic tunneling junction device of claim 12 , wherein
the non-magnetic metal of the free layer comprises at least one metal element selected from Ru, Ir, Zn, Ga, Sn, W, Sb, V, Cr, Ge, Rh, and In, and
the metal in a metal oxide of the second oxide layer comprises at least one metal element selected from Ti, Ta, Al, Zr, Si, Hf, Tb, Sc, and Y.
16 . The magnetic tunneling junction device of claim 12 , wherein
a doping concentration of the non-magnetic metal in the free layer is in a range of about 5 at % to about 50 at %.
17 . The magnetic tunneling junction device of claim 12 , wherein
the free layer further comprises boron (B), and
a boron concentration of the free layer is in a range of about 5 at % to about 50 at %.
18 . The magnetic tunneling junction device of claim 17 , wherein
the second oxide layer further comprises boron absorbed from the free layer.
19 . A memory device comprising:
a plurality of memory cells each comprising a switching device connected to a magnetic tunneling junction device,
wherein the magnetic tunneling junction device comprises,
a free layer having a first surface and a second surface opposite the first surface,
a pinned layer facing the first surface of the free layer,
a first oxide layer between the pinned layer and the free layer,
a second oxide layer on the second surface of the free layer, and
a capping metal layer in contact with the second oxide layer,
wherein
the free layer comprises a magnetic material doped with a non-magnetic metal, and
the capping metal layer comprises a metal different from the non-magnetic metal of the free layer.