Nitride diffusion barrier structure for spintronic applications

A perpendicular magnetic tunnel junction (p-MTJ) structure formed on a substrate, comprising:

• (a) a pinned layer (PL);
• (b) a tunnel barrier layer with a first surface that adjoins the PL, and a second surface that contacts a free layer (FL);
• (c) the FL that has perpendicular magnetic anisotropy (PMA) as a result of a first oxide interface with the tunnel barrier layer;
• (d) a spacer that adjoins the FL on a side thereof that is opposite to the tunnel barrier layer;
• and
• (e) a nitride diffusion barrier (NDB) that is an uppermost layer in the p-MTJ structure, wherein the p-MTJ structure has a width “w” determined by a sidewall that extends from a top surface of the NL to a top surface of the substrate comprising:
• (1) a nitride layer (NL) that is TaON, WON, NbON, or TiON or has a M1N or M1ON composition where M1 is a metal or alloy that is one or more of V, Cr, Zr, Mo, Hf, and Mg;
• and
• (2) a partially oxidized metal oxide (MOx) layer that adjoins the NL and is formed between the NL and the spacer, and wherein M is one or more of Zr, Zn, Sr, Cr, Pt, Cu, Au, Ag, Cd, Ir, Rh, Co, Fe, CoFe, CoFeB, CoB, FeB, CoFeNi, or CoFeNiB.

A method of forming a perpendicular magnetic tunnel junction (p-MTJ), comprising:

• (a) providing a stack of layers comprised of a pinned layer, tunnel barrier layer, free layer (FL), and spacer that are sequentially formed on a seed layer;
• (b) forming a nitride diffusion barrier (NDB) with a L2/L1/NL configuration on the spacer, wherein the NDB comprises:
• (1) an oxygen diffusion barrier layer (L2) that is a partially oxidized metal or alloy of Cr, Pt, Cu, Ag, Au, Zn, Cd, Ir, Zr, Sr, Rh, Co, Fe, CoFe, CoFeB, CoB, FeB, CoFeNi, and CoFeNiB that blocks oxygen diffusion to a nitride layer (NL);
• (2) a nitrogen diffusion barrier layer (L1) that substantially prevents nitrogen diffusion from the NL to the spacer and FL;
• and
• (3) the NL that has a M2M3N or M2M3ON composition where M2 is one of B, Al, Si, Ga, In, and TI, and M3 is one or more of Pt, Au, Ag, Mg, Ca, Sr, Ba, Sc, Y, La, Co, Fe, Mn, Ir, Ni, Pd, Zn, Cu, Ti, V, Cr, Zr, Nb, Hf, and Ta such that the NL is a conductive alloy layer, or has M3 conductive channels formed in a M2N or M2ON insulating matrix, and is the uppermost layer in the p-MTJ;
• and
• (c) annealing the stack of layers to a temperature proximate to 400° C.

A method of forming a perpendicular magnetic tunnel junction (p-MTJ), comprising:

• (a) providing a stack of layers comprised of a pinned layer, tunnel barrier layer, free layer (FL), and spacer that are sequentially formed on a seed layer;
• (b) forming a nitride diffusion barrier (NDB) with a L2/L1/NL configuration on the spacer, wherein the NDB comprises:
• (1) an oxygen diffusion barrier layer (L2) that is a partially oxidized metal or alloy of Cr, Pt, Cu, Ag, Au, Zn, Cd, Ir, Zr, Sr, Rh, Co, Fe, CoFe, CoFeB, CoB, FeB, CoFeNi, and CoFeNIB that blocks oxygen diffusion to a nitride layer (NL);
• (2) a nitrogen diffusion barrier layer (L1) that substantially prevents nitrogen diffusion from the NL to the spacer and FL;
• and
• (3) the NL that is TaON, NbON, WON, or TiON or has a M1N or M1ON composition where M1 is a metal or alloy that is one or more of V, Cr, Zr, Mo, Hf, and Mg, and is the uppermost layer in the p-MTJ;
• and
• (c) annealing the stack of layers to a temperature proximate to 400° C.

A perpendicular magnetic tunnel junction (p-MTJ) structure formed on a substrate, comprising:

• (a) a pinned layer (PL);
• (b) a tunnel barrier layer with a first surface that adjoins the PL, and a second surface that contacts a free layer (FL);
• (c) the FL that has perpendicular magnetic anisotropy (PMA) as a result of a first oxide interface with the tunnel barrier layer;
• and
• (d) a nitride diffusion barrier (NDB), comprising:
• (1) a nitride layer (NL) that is M2M3N or M2M3ON where M2 is one of B, Al, Si, Ga, In, and TI, and M3 is one or more of Pt, Au, Ag, Mg, Ca, Sr, Ba, Sc, Y, La, Co, Fe, Mn, Ru, Rh, Ir, Ni, Pd, Zn, Cu, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W such that the NL is a conductive alloy layer, or has M3 conductive channels formed in a M2N or M2ON insulating matrix, and is an uppermost layer in the p-MTJ structure wherein the p-MTJ structure has a width “w” determined by a sidewall that extends from a top surface of the NL to a top surface of the substrate;
• and
• (2) a partially oxidized metal oxide (MOx) layer that adjoins the NL and is formed between the NL and the FL such that a FL/MOx interface is a second oxide interface to induce additional PMA in the FL, wherein M is one or more of Cr, Pt, Cu, Au, Ag, Zn, Cd, Sn, Ir, Rh, and Zr.

A perpendicular magnetic tunnel junction (p-MTJ) structure formed on a substrate, comprising:

• (a) a pinned layer (PL);
• (b) a tunnel barrier layer with a first surface that adjoins the PL, and a second surface that contacts a free layer (FL);
• (c) the FL that has perpendicular magnetic anisotropy (PMA) as a result of a first oxide interface with the tunnel barrier layer;
• (d) a spacer that is a metal oxide or metal oxynitride and adjoins the FL on a side thereof that is opposite to the tunnel barrier layer thereby forming a second oxide interface with the FL;
• and
• (e) a nitride diffusion barrier (NDB) that is an uppermost layer in the p-MTJ structure, wherein the p-MTJ structure has a width “w” determined by a sidewall that extends from a top surface of the NL to a top surface of the substrate comprising:
• (1) a nitride layer (NL) that has a M2M3N or M2M3ON composition where M2 is one of B, Al, Si, Ga, In, and TI, and M3 is one or more of Pt, Au, Ag, Mg, Ca, Sr, Ba, Sc, Y, La, Co, Fe, Mn, Ru, Rh, Ir, Ni, Pd, Zn, Cu, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W such that the NL is a conductive alloy layer, or has M3 conductive channels formed in a M2N or M2ON insulating matrix;
• and
• (2) a partially oxidized metal oxide (MOx) layer that adjoins the NL and is formed between the NL and the spacer, and wherein M is one or more of Zr, Nb, Ta, Zn, Sr, Cr, Cu, Au, Ag, Cd, Sr, Ir, Co, Fe, CoFe, CoFeB, CoB, FeB, CoFeNi, or CoFeNiB.