Magnetic memory device
A width and a thickness of a bit line are represented as W1 and T1, respectively, a thickness of a digit line is represented as T2, and a distance from a center of the digit line in a thickness direction to a center of a free layer of an MTJ element in the thickness direction is represented as L1. A width of the digit line is represented as W2, and a distance from a center of the bit line in the thickness direction to the center of the free layer of the MTJ element in the thickness direction is represented as L2. The distances L1 and L2 and the cross-sectional areas S1 and S2 are set in such a manner that when L1/L2≧1, a relation of (⅓)·(L1/L2 )≦S2/S1≦1 is satisfied and when L1/L2≦1, a relation of 1≦S2/S1≦3(L1 /L2) is satisfied.
1. A magnetic memory device comprising:
first and second write wires that intersect each other in a non-contact manner; and
a magnetic tunnel junction element which is arranged in an intersection of said first and second write wires and includes a magnetic tunnel junction, wherein
said magnetic tunnel junction element has a free layer consisting of a ferromagnetic material in which a magnetization direction is variable with a magnetic field generated by current flowing through said first and second write wires, and
in the case where a distance between a center of said first write wire in a thickness direction and a center of said free layer in the thickness direction is represented as L1,
a distance between a center of said second write wire in the thickness direction and a center of said free layer in the thickness direction is represented as L2,
a cross-sectional area of said first write wire in a width direction is represented as S2 and
a cross-sectional area of said second write wire in a width direction is referred to as S1,
said distance L1, said distance L2, said cross-sectional area S1, and said cross-sectional area S2 are set in such a manner that:
when a ratio of said distance L1 to said distance L2 is L1/L2 ≧1
a relation of(⅓)·(L1/L2)≦S2/S1≦1 is satisfied;
when the ratio of said distance L1 to said distance L2 is L1 /L2≦1,
a relation of 1≦S2/S1≦ 3 (L1/L2) is satisfied;
when a relation between said distance L1 and said distance L2 is L1 >L2,
said second write wire is made of a metal material having higher melting point than a melting point of a metal material for said first write wire, and
as a combination of metal materials for said first write wire and said second write wire, one combination is selected from among aluminum series and copper series, aluminum series and tungsten series, aluminum series and titanium series, copper series and tungsten series and copper series and titanium series; and
when the relation between said distance L1 and said distance L2 is L1 <L2,
said first write wire is made of a metal material having higher melting point than a melting point of a material for said second write wire, and
as a combination of metal materials for said first write wire and said second write wire, one combination is selected from among copper series and aluminum series, tungsten series and aluminum series, titanium series and aluminum series, tungsten series and copper series, and titanium series and copper series.
2. A magnetic memory device comprising:
first and second write wires that intersect each other in a non-contact manner; and
a magnetic tunnel junction element which is arranged in an intersection of said first and second write wires and includes a magnetic tunnel junction, wherein
said magnetic tunnel junction element has a free layer consisting of a ferromagnetic material in which a magnetization direction is variable with a magnetic field generated by current flowing through said first and second write wires, and
in the case where a distance between a center of said first write wire in a thickness direction and a center of said free layer in the thickness direction is represented as L1,
a distance between a center of said second write wire in the thickness direction and a center of said free layer in the thickness direction is represented as L2,
a cross-sectional area of said first write wire in a width direction is represented as S2 and
a cross-sectional area of said second write wire in a width direction is referred to as S1,
said distance L1, said distance L2, said cross-sectional area S1, and said cross-sectional area S2 are set in such a manner that:
when a ratio of said distance L1 to said distance L2 is L1 /L2≧1,
a relation of (⅓)·(L1/L2)≦S2/S1≦1 is satisfied;
when the ratio of said distance L1 to said distance L2 is L1/L2≦1,
a relation of 1≦S2/S1≦3(L1/L2) is satisfied;
when a relation between said cross-sectional area S1and said cross-sectional area S2is S1>S2,
said first write wire is made of a metal material having higher melting point than a melting point of a material for said second write wire, and
as a combination of metal materials for said first write wire and said second write wire,
one combination is selected from among copper series and aluminum series, tungsten series and aluminum series, titanium series and aluminum series, tungsten series and copper series, and titanium series and copper series; and
when the relation between said cross-sectional area S1and said cross-sectional area S2is S1<S2,
said second write wire is made of a metal material having higher melting point than a melting point of a material for said first write wire, and
as a combination of metal materials for said first write wire and said second write wire,
one combination is selected from among aluminum series and copper series, aluminum series and tungsten series, aluminum series and titanium series, copper series and tungsten series, and copper series and titanium series.
3. The magnetic memory device according to claim 1 , wherein
as a metal material of said aluminum series, one metal material is selected from among aluminum silicide (AlSi), AlSiCu, and AlCu, and
as a metal material for said copper series, pure copper formed by plating technique or by sputtering technique is selected, and
as a metal material for said tungsten series, pure tungsten or tungsten suicide (WS1 2 ) is selected, and
as a metal material for said titanium series, titanium nitride (TiN) or titanium silicide (TiSi 2 ) is selected.
4. The magnetic memory device according to claim 2 , wherein
as a metal material for said aluminum series, one material is selected from among aluminum silicide (AlSi), AlSiCu, and AlCu, and
as a metal material for said copper series, pure copper formed by plating technique or by sputtering technique is selected, and
as a metal material for said tungsten series, pure tungsten or tungsten suicide (WSi 2 ) is selected, and
as a metal material for said titanium series, titanium nitride (TiN) or titanium silicide (TiSi 2 ) is selected.