Magnetic memory device and manufacturing method of magnetic memory device
According to one embodiment, a magnetic memory device comprises a first conductor, a second conductor, a third conductor, a fourth conductor, a first layer stack, a second layer stack, and a third layer stack. The first layer stack, the second layer stack, and the third layer stack are arranged between the first conductor and the third conductor, between the first conductor and the fourth conductor, and between the second conductor and the third conductor, respectively. A height from a first portion to a first plane and a height from a second portion to the first plane are within a first range, the first portion being between the first layer stack and the third layer stack, and the second portion being between the second layer stack and the third layer stack.
1 . A magnetic memory device comprising:
a first conductor and a second conductor each extending in a first direction and being separated from each other and aligned in a second direction that intersects the first direction;
a third conductor and a fourth conductor each extending in the second direction, the third conductor and the fourth conductor being arranged above the first conductor and the second conductor and being separated from each other and aligned in the first direction;
a first layer stack arranged between the first conductor and the third conductor, and including a first magnetoresistive effect element;
a second layer stack arranged between the first conductor and the fourth conductor, and including a second magnetoresistive effect element;
a third layer stack arranged between the second conductor and the third conductor, and including a third magnetoresistive effect element; and
an insulator arranged between the first conductor and the second conductor, a position of the insulator in a third direction that intersects both the first direction and the second direction being lower than positions of the first layer stack, the second layer stack, and the third layer stack in the third direction,
wherein:
a shape of the first layer stack is circular when viewed along the third direction,
a shape of the second layer stack is circular when viewed along the third direction,
a shape of the third layer stack is circular when viewed along the third direction,
a top surface of the first layer stack, a top surface of the second layer stack, and a top surface of the third layer stack are on a same first plane extending along the first direction and the second direction,
the insulator includes a first portion between the first layer stack and the third layer stack, and a second portion between the second layer stack and the third layer stack,
the first conductor includes a third portion between the first layer stack and the second layer stack,
a first distance from a top surface of the first portion to the first plane, a second distance from a top surface of the second portion to the first plane, and a third distance from a top surface of the third portion to the first plane are substantially equal, and
a height of a top surface of a first portion of the first conductor that overlaps with the first layer stack along the third direction is greater than a height of the top surface of the third portion, and
a height of a top surface of a second portion of the first conductor that overlaps with the second layer stack along the third direction is greater than the height of the top surface of the third portion.
2 . The device of claim 1 , wherein a distance between the first layer stack and the second layer stack is 50 nanometers or smaller.
3 . The device of claim 2 , wherein:
the first magnetoresistive effect element includes a first ferromagnetic layer, a second ferromagnetic layer, and a non-magnetic layer between the first ferromagnetic layer and the second ferromagnetic layer, and
an outer diameter of the circular shape in the non-magnetic layer is 20 nanometers or smaller.
4 . The device of claim 3 , wherein the non-magnetic layer includes a magnesium (Mg) oxide.
5 . The device of claim 4 , wherein the first ferromagnetic layer and the second ferromagnetic layer include at least one element selected from iron (Fe), cobalt (Co), and nickel (Ni).
6 . The device of claim 5 , wherein the first ferromagnetic layer takes a first resistance value in accordance with a first current flowing from the first ferromagnetic layer to the second ferromagnetic layer, and takes a second resistance value in accordance with a second current flowing from the second ferromagnetic layer to the first ferromagnetic layer.
7 . The device of claim 6 , wherein the first resistance value is smaller than the second resistance value.
8 . The device of claim 1 , wherein the first layer stack further includes a switching element serially connected to the first magnetoresistive effect element.
9 . The device of claim 1 , wherein:
a position of the top surface of each of the first and second portions along the third direction is below a position of an uppermost surface of the insulator along the third direction, and
a position of the top surface of the third portion along the third direction is below a position of an uppermost surface of the first conductor along the third direction.
10 . A magnetic memory device comprising:
a first conductor and a second conductor each extending in a first direction and being separated from each other and aligned in a second direction that intersects the first direction;
a third conductor and a fourth conductor each extending in the second direction, the third conductor and the fourth conductor being arranged above the first conductor and the second conductor and being separated from each other and aligned in the first direction;
a first layer stack arranged between the first conductor and the third conductor, and including a first magnetoresistive effect element;
a second layer stack arranged between the first conductor and the fourth conductor, and including a second magnetoresistive effect element;
a third layer stack arranged between the second conductor and the third conductor, and including a third magnetoresistive effect element; and
an insulator arranged between the first conductor and the second conductor, a position of the insulator in a third direction that intersects both the first direction and the second direction being lower than positions of the first layer stack, the second layer stack, and the third layer stack in the third direction,
wherein:
a shape of the first layer stack is circular when viewed along the third direction,
a shape of the second layer stack is circular when viewed along the third direction,
a shape of the third layer stack is circular when viewed along the third direction,
a top surface of the first layer stack, a top surface of the second layer stack, and a top surface of the third layer stack are on a same first plane extending along the first direction and the second direction,
the insulator includes a first portion between the first layer stack and the third layer stack, a second portion between the second layer stack and the third layer stack, and a third portion between the first layer stack and the second layer stack and above the first conductor, and
a first distance from a top surface of the first portion to the first plane, a second distance from a top surface of the second portion to the first plane, and a third distance from a top surface of the third portion to the first plane are substantially equal.
11 . A magnetic memory device comprising:
a first conductor and a second conductor each extending in a first direction and being separated from each other and aligned in a second direction that intersects the first direction;
a third conductor and a fourth conductor each extending in the second direction, the third conductor and the fourth conductor being arranged above the first conductor and the second conductor and being separated from each other and aligned in the first direction;
a first layer stack arranged between the first conductor and the third conductor, and including a first magnetoresistive effect element;
a second layer stack arranged between the first conductor and the fourth conductor, and including a second magnetoresistive effect element;
a third layer stack arranged between the second conductor and the third conductor, and including a third magnetoresistive effect element; and
an insulator arranged between the first conductor and the second conductor, a position of the insulator in a third direction that intersects both the first direction and the second direction being lower than positions of the first layer stack, the second layer stack, and the third layer stack in the third direction,
wherein:
a shape of the first layer stack is circular when viewed along the third direction,
a shape of the second layer stack is circular when viewed along the third direction,
a shape of the third layer stack is circular when viewed along the third direction,
a height of the insulator in the third direction from a bottom surface to a top surface thereof varies along a length of the insulator in the second direction so as to include at least two different heights,
a height of the first conductor in the third direction from a bottom surface to a top surface thereof varies along a length of the first conductor in the first direction so as to include at least two different heights, and
the first conductor has a substantially same thickness along a length of the first conductor in the second direction.