Three-dimensional arrays with MTJ devices including a free magnetic trench layer and a planar reference magnetic layer

1. A device comprising:

a first reference magnetic layer including a first plurality of trenches;

a plurality of sections of a first tunnel barrier layer disposed on the walls of the first plurality of trenches;

a plurality of sections of a first free magnetic layer disposed on the plurality of sections of the first tunnel barrier layer in the first plurality of trenches;

a plurality of sections of a first conductive layer disposed on the plurality of sections of the first free magnetic layer in the first plurality of trenches;

a first plurality of insulator blocks disposed between corresponding sections of the first tunnel barrier layer, corresponding sections of the first free magnetic layer and corresponding sections of the first conductive layer in the first plurality of trenches;

a first insulator layer disposed on a first side of the first reference magnetic layer;

a first plurality of interconnects disposed through the first insulator layer and coupled to respective ones of the plurality of sections of the first conductive layer;

a second reference magnetic layer including a second plurality of trenches;

a plurality of sections of a second tunnel barrier layer disposed on the walls of the second plurality of trenches;

a plurality of sections of a second free magnetic layer disposed on the plurality of sections of the second tunnel barrier layer in the second plurality of trenches;

a plurality of sections of a second conductive layer disposed on the plurality of sections of the second free magnetic layer in the second plurality of trenches;

a second plurality of insulator blocks disposed between corresponding sections of the second tunnel barrier layer, corresponding sections of the second free magnetic layer and corresponding sections of the second conductive layer in the second plurality of trenches;

a second insulator layer disposed between a first side of the second reference magnetic layer and a second side of the first reference magnetic layer; and

a second plurality of interconnects disposed through the second insulator layer and coupled between respective ones of the plurality of sections of the first conductive layer and the second conductive layer.

2. The device of claim 1 , further comprising:

a third reference magnetic layer including a third plurality of trenches;

a plurality of sections of a third tunnel barrier layer disposed on the walls of the third plurality of trenches;

a plurality of sections of a third free magnetic layer disposed on the plurality of sections of the third tunnel barrier layer in the third plurality of trenches;

a plurality of sections of a third conductive layer disposed on the plurality of sections of the third free magnetic layer in the third plurality of trenches; and

a third plurality of insulator blocks disposed between corresponding sections of the third tunnel barrier layer, corresponding sections of the third free magnetic layer and corresponding sections of the third conductive layer in the third plurality of trenches;

a third insulator layer disposed between a first side of the third reference magnetic layer and a second side of the second reference magnetic layer; and

a third plurality of interconnects disposed through the third insulator layer and coupled between respective ones of the plurality of sections of the second conductive layer and the third conductive layer.

3. The device of claim 1 , further comprising:

a plurality of sections of a first non-magnetic capping layer disposed between the plurality of sections of the first free magnetic layer and the plurality of sections of the first conductive layer in the first plurality of trenches; and

a plurality of sections of a second non-magnetic capping layer disposed between the plurality of sections of the second free magnetic layer and the plurality of sections of the second conductive layer in the second plurality of trenches.

4. The device of claim 1 , further comprising:

a first bit line disposed on the second side of the first reference magnetic layer, across one or more of the first plurality of insulator blocks and coupled to portions of the first reference magnetic layer; and

a second bit line disposed on a second side of the second reference magnetic layer, across one or more of the second plurality of insulator blocks and coupled to portions of the second reference magnetic layer.

5. The device of claim 1 , wherein:

the first plurality of trenches have a taper of approximately 10-45 degrees from the second side of the first reference magnetic layer to the first side of the first reference magnetic layer; and

the second plurality of trenches have a taper of approximately 10-45 degrees from a second side of the second reference magnetic layer to the first side of the second reference magnetic layer.

6. The device of claim 1 , wherein:

the first and second free magnetic layers include a Cobalt-Iron-Boron (Co—Fe—B) alloy;

the first and second conductive layers include one or more of Copper (Cu), copper alloy, Aluminum (Al), aluminum alloy, Ruthenium (Ru) or ruthenium alloy;

the first and second tunnel insulator layers include one or more of Magnesium Oxide (MgO), Silicon Oxide (SiOx), Aluminum Oxide (AlOx) or Titanium Oxide (TiOx); and

the first and second reference magnetic layers includes a Cobalt-Iron-Boron (Co—Fe—B) alloy.

7. The device of claim 1 , wherein:

a magnetic field of the first and second reference magnetic layers have a fixed polarization substantially parallel to a major planar orientation of the first and second reference magnetic layers; and

a magnetic field of the first and second free magnetic layers have a polarization substantially parallel to the major planar orientation of the first and second reference magnetic layers and selectively switchable between being substantially parallel and substantially antiparallel to the magnetic field of the first and second reference magnetic layers.

8. The device of claim 7 , wherein:

the magnetic field of a given section of the first free magnetic layers is configured to switch to being substantially parallel to the magnetic field of the first reference magnetic layers in response to a current flow in a first direction through a corresponding section of the first conductive layer and to switch to being substantially anti-parallel to the magnetic field of the first reference magnetic layer in response to a current flow in a second direction through the corresponding section the first conductive layer; and

the magnetic field of a given section of the second free magnetic layers is configured to switch to being substantially parallel to the magnetic field of the second reference magnetic layers in response to a current flow in a first direction through a corresponding section of the second conductive layer and to switch to being substantially anti-parallel to the magnetic field of the second reference magnetic layer in response to a current flow in a second direction through the corresponding section the second conductive layer.

9. The device of claim 1 , wherein:

a magnetic field of the first and second reference magnetic layers have a fixed polarization substantially perpendicular to a major planar orientation of the first and second reference magnetic layer; and

a magnetic field of the first and second free magnetic layers have a polarization substantially perpendicular to the major planar orientation of the first and second reference magnetic layers and selectively switchable between being substantially parallel and substantially antiparallel to the magnetic field of the first and second reference magnetic layers.

10. The device of claim 9 , wherein:

the magnetic field of a corresponding section of the first free magnetic layer is configured to switch to being substantially parallel to the magnetic field of the first reference magnetic layer in response to a current flow in a first direction through a corresponding section the first conductive layer and to switch to being substantially anti-parallel to the magnetic field of the first reference magnetic layer in response to a current flow in a second direction through the corresponding portion of the first conductive layer; and

the magnetic field of a corresponding section of the second free magnetic layer is configured to switch to being substantially parallel to the magnetic field of the second reference magnetic layer in response to a current flow in a first direction through a corresponding section the second conductive layer and to switch to being substantially anti-parallel to the magnetic field of the second reference magnetic layer in response to a current flow in a second direction through the corresponding portion of the second conductive layer.

11. A memory device comprising:

an array of Magnetic Tunnel Junction (MTJ) cells arranged in cell columns and cell rows in a plurality of cell levels, wherein the MTJ cells in corresponding cell column and cell row positions in the plurality of cell levels are coupled together in cell strings, the array of MTJ cells including:

a first reference magnetic layer including a first plurality of trenches;

a plurality of sections of a first tunnel barrier layer disposed on the walls of the first plurality of trenches;

a plurality of sections of a first free magnetic layer disposed on the plurality of sections of the first tunnel barrier layer in the first plurality of trenches;

a plurality of sections of a first conductive layer disposed on the plurality of sections of the first free magnetic layer in the first plurality of trenches;

a first plurality of insulator blocks disposed between corresponding sections of the first tunnel barrier layer, corresponding sections of the first free magnetic layer and corresponding sections of the first conductive layer in the first plurality of trenches;

a first insulator layer disposed on a first side of the first reference magnetic layer,

a first plurality of interconnects disposed through the first insulator layer and coupled to respective ones of the plurality of sections of the first conductive layer;

a second reference magnetic layer including a second plurality of trenches;

a plurality of sections of a second tunnel barrier layer disposed on the walls of the second plurality of trenches;

a plurality of sections of a second free magnetic layer disposed on the plurality of sections of the second tunnel barrier layer in the second plurality of trenches;

a plurality of sections of a second conductive layer disposed on the plurality of sections of the second free magnetic layer in the second plurality of trenches; and

a second plurality of insulator blocks disposed between corresponding sections of the second tunnel barrier layer, corresponding sections of the second free magnetic layer and corresponding sections of the second conductive layer in the second plurality of trenches;

a second insulator layer disposed between a first side of the second reference magnetic layer and a second side of the first reference magnetic layer; and

a second plurality of interconnects disposed through the second insulator layer and coupled between respective ones of the plurality of sections of the first conductive layer and the second conductive layer;

a first bit line coupled to the first reference magnetic layer;

a second bit line coupled to the second reference magnetic layer; and

a plurality of select transistors, each select transistor coupled to respective sections of the first and second conductive layers.

12. The memory device of claim 11 , further comprising:

a plurality of word lines, each word line coupled to gates of a set of the plurality of select transistors arranged in a corresponding row; and

a plurality of source lines, each source line coupled to sources of a set of the plurality of select transistors arranged in a corresponding column.

13. The memory device of claim 11 , further comprising:

a plurality of blocks of the array of MTJ cells arranged in columns and rows.

14. The memory device of claim 13 , further comprising:

a plurality of global bit lines, each global bit line coupled to a set of bit lines in a corresponding column of the plurality of blocks of the array of MTJ cells.

15. The memory device of claim 11 , wherein

a magnetic field of the first and second reference magnetic layers have a fixed polarization substantially parallel to a major planar orientation of the first and second reference magnetic layers; and

a magnetic field of the first and second free magnetic layers have a polarization substantially parallel to the major planar orientation of the first and second reference magnetic layers and selectively switchable between being substantially parallel and substantially antiparallel to the magnetic field of the first and second reference magnetic layers.

16. The memory device of claim 15 , wherein;

the magnetic field of a given section of the first free magnetic layers is configured to switch to being substantially parallel to the magnetic field of the first reference magnetic layers in response to a current flow in a first direction through a corresponding section of the first conductive layer and to switch to being substantially anti-parallel to the magnetic field of the first reference magnetic layer in response to a current flow in a second direction through the corresponding section the first conductive layer; and

the magnetic field of a given section of the second free magnetic layers is configured to switch to being substantially parallel to the magnetic field of the second reference magnetic layers in response to a current flow in a first direction through a corresponding section of the second conductive layer and to switch to being substantially anti-parallel to the magnetic field of the second reference magnetic layer in response to a current flow in a second direction through the corresponding section the second conductive layer.

17. The memory device of claim 11 , wherein

a magnetic field of the first and second reference magnetic layers have a fixed polarization substantially perpendicular to a major planar orientation of the first and second reference magnetic layer; and

a magnetic field of the first and second free magnetic layers have a polarization substantially perpendicular to the major planar orientation of the first and second reference magnetic layers and selectively switchable between being substantially parallel and substantially antiparallel to the magnetic field of the first and second reference magnetic layers.

18. The memory device of claim 17 , wherein:

the magnetic field of a corresponding section of the first free magnetic layer is configured to switch to being substantially parallel to the magnetic field of the first reference magnetic layer in response to a current flow in a first direction through a corresponding section the first conductive layer and to switch to being substantially anti-parallel to the magnetic field of the first reference magnetic layer in response to a current flow in a second direction through the corresponding portion of the first conductive layer; and

the magnetic field of a corresponding section of the second free magnetic layer is configured to switch to being substantially parallel to the magnetic field of the second reference magnetic layer in response to a current flow in a first direction through a corresponding section the second conductive layer and to switch to being substantially anti-parallel to the magnetic field of the second reference magnetic layer in response to a current flow in a second direction through the corresponding portion of the second conductive layer.