MEMORY SYSTEM HAVING THERMALLY STABLE PERPENDICULAR MAGNETO TUNNEL JUNCTION (MTJ) AND A METHOD OF MANUFACTURING SAME
A spin-torque transfer magnetic random access memory (STTMRAM) element employed to store a state based on the magnetic orientation of a free layer, the STTMRAM element is made of a first perpendicular free layer (PFL) including a first perpendicular enhancement layer (PEL). The first PFL is formed on top of a seed layer. The STTMRAM element further includes a barrier layer formed on top of the first PFL and a second perpendicular reference layer (PRL) that has a second PEL, the second PRL is formed on top of the barrier layer. The STTMRAM element further includes a capping layer that is formed on top of the second PRL.
1 . A spin transfer torque magnetic random access memory (STTMRAM) element comprising:
a non-magnetic seed layer;
a first magnetic layer structure having a perpendicular magnetization direction formed on said non-magnetic seed layer;
a second magnetic layer structure having a perpendicular magnetization direction separated from said first magnetic layer structure by an insulating tunneling barrier layer; and
a non-magnetic capping layer formed on top of said second magnetic layer structure,
wherein at least one of said first and second magnetic layer structures includes a first CoFe based alloy magnetic layer and a second CoFe based alloy magnetic layer with a non-magnetic perpendicular enhancement layer (PEL) interposed therebetween.
2 . The STTMRAM element as recited in claim 1 , wherein said first magnetic layer structure includes a first CoFeB magnetic layer and a second CoFeB magnetic layer with a non-magnetic PEL interposed therebetween, said non-magnetic seed layer is made of magnesium oxide (MgO).
3 . The STTMRAM element as recited in claim 2 , wherein said non-magnetic PEL is made of tantalum (Ta).
4 . The STTMRAM element as recited in claim 2 , wherein said non-magnetic PEL is made of a material selected from a group consisting of hafnium (Hf), niobium (Nb), vanadium (V), yttrium (Y), rhenium (Re), tungsten (W), chromium (Cr), molybdenum (Mo), ruthenium (Ru), and any combination thereof.
5 . The STTMRAM element as recited in claim 2 , wherein the magnetization direction of said first magnetic layer structure can be switched with a polarization current.
6 . The STTMRAM element as recited in claim 2 , wherein the magnetization direction of said first magnetic layer structure is substantially fixed.
7 . The STTMRAM element as recited in claim 1 , wherein said second magnetic layer structure includes a first CoFeB magnetic layer and a second CoFeB magnetic layer with a non-magnetic PEL interposed therebetween, said non-magnetic capping layer is made of magnesium oxide (MgO).
8 . The STTMRAM element as recited in claim 7 , wherein said non-magnetic PEL is made of tantalum (Ta).
9 . The STTMRAM element as recited in claim 7 , wherein said non-magnetic PEL is made of a material selected from a group consisting of hafnium (Hf), niobium (Nb), vanadium (V), yttrium (Y), rhenium (Re), tungsten (W), chromium (Cr), molybdenum (Mo), ruthenium (Ru), and any combination thereof.
10 . The STTMRAM element as recited in claim 7 , wherein the magnetization direction of said second magnetic layer structure can be switched with a polarization current.
11 . The STTMRAM element as recited in claim 7 , wherein the magnetization direction of said second magnetic layer structure is substantially fixed.
12 . A spin transfer torque magnetic random access memory (STTMRAM) element comprising:
a non-magnetic seed layer;
a magnetic free layer structure formed on said non-magnetic seed layer and having a variable magnetization direction perpendicular to the film plane thereof;
a magnetic reference layer structure having a fixed magnetization direction perpendicular to the film plane thereof and separated from said magnetic free layer structure by an insulating tunneling barrier layer; and
a non-magnetic capping layer formed on top of said magnetic reference layer structure,
wherein at least one of said magnetic free and reference layer structures includes a first CoFe based alloy magnetic layer and a second CoFe based alloy magnetic layer with a non-magnetic perpendicular enhancement layer (PEL) interposed therebetween.
13 . The STTMRAM element as recited in claim 12 , wherein said magnetic free layer structure includes a first CoFeB magnetic layer and a second CoFeB magnetic layer with a non-magnetic PEL interposed therebetween, said non-magnetic seed layer is made of magnesium oxide (MgO).
14 . The STTMRAM element as recited in claim 12 , wherein said magnetic reference layer structure includes a first CoFeB magnetic layer and a second CoFeB magnetic layer with a non-magnetic PEL interposed therebetween, said non-magnetic capping layer is made of magnesium oxide (MgO).
15 . The STTMRAM element as recited in claim 12 , wherein said non-magnetic PEL is made of tantalum (Ta).
16 . The STTMRAM element as recited in claim 12 , wherein said non-magnetic PEL is made of a material selected from a group consisting of hafnium (Hf), niobium (Nb), vanadium (V), yttrium (Y), rhenium (Re), tungsten (W), chromium (Cr), molybdenum (Mo), ruthenium (Ru), and any combination thereof.
17 . A spin transfer torque magnetic random access memory (STTMRAM) element comprising:
a non-magnetic seed layer;
a magnetic reference layer structure formed on said non-magnetic seed layer and having a fixed magnetization direction perpendicular to the film plane thereof;
a magnetic free layer structure having a variable magnetization direction perpendicular to the film plane thereof and separated from said magnetic reference layer structure by an insulating tunneling barrier layer; and
a non-magnetic capping layer formed on top of said magnetic free layer structure,
wherein at least one of said magnetic free and reference layer structures includes a first CoFe based alloy magnetic layer and a second CoFe based alloy magnetic layer with a non-magnetic perpendicular enhancement layer (PEL) interposed therebetween.
18 . The STTMRAM element as recited in claim 17 , wherein said magnetic free layer structure includes a first CoFeB magnetic layer and a second CoFeB magnetic layer with a non-magnetic PEL interposed therebetween, said non-magnetic seed layer is made of magnesium oxide (MgO).
19 . The STTMRAM element as recited in claim 17 , wherein said magnetic reference layer structure includes a first CoFeB magnetic layer and a second CoFeB magnetic layer with a non-magnetic PEL interposed therebetween, said non-magnetic capping layer is made of magnesium oxide (MgO).
20 . The STTMRAM element as recited in claim 17 , wherein said non-magnetic PEL is made of tantalum (Ta).
21 . The STTMRAM element as recited in claim 17 , wherein said non-magnetic PEL is made of a material selected from a group consisting of hafnium (Hf), niobium (Nb), vanadium (V), yttrium (Y), rhenium (Re), tungsten (W), chromium (Cr), molybdenum (Mo), ruthenium (Ru), and any combination thereof.