Magnetic Tunnel Junction Devices Including an Annular Free Magnetic Layer and a Planar Reference Magnetic Layer
A Magnetic Tunnel Junction (MTJ) can include an annular structure and a planar reference magnetic layer disposed about the annular structure. The annular structure can include an annular non-magnetic layer disposed about an annular conductive layer, an annular free magnetic layer disposed about the annular nonmagnetic layer, and an annular tunnel insulator disposed about the annular free magnetic layer. The planar reference magnetic layer can be separated from the free magnetic layer by the annular tunnel barrier layer.
1 . A Magnetic Tunnel Junction (MTJ) comprising:
an annular structure including an annular non-magnetic layer disposed about an annular conductive layer, an annular free magnetic layer disposed about the annular non-magnetic layer, and an annular tunnel insulator disposed about the annular free magnetic layer;
a planar reference magnetic layer disposed about the annular structure and separated from the free magnetic layer by the annular tunnel barrier layer.
2 . The MTJ of claim 1 , wherein the annular structure comprises a conical structure including a conical non-magnetic layer disposed about a conical portion of the conductive layer, a conical free magnetic layer disposed about the conical non-magnetic layer, and a conical tunnel barrier layer disposed about the conical free magnetic layer.
3 . The MTJ of claim 2 , wherein the conical structure has a taper of approximately 10-45 degrees from a first side of the planar reference magnetic layer to a second side of the planar reference magnetic layer.
4 . The MTJ of claim 1 , further comprising:
a first set of one or more additional layers disposed about the annular structure and on a first side of the planar reference magnetic layer; and
a second set of one or more additional layers disposed about the annular structure and on a second side of the planar reference magnetic layer.
5 . The MTJ of claim 1 , wherein:
the annular free magnetic layer includes a Cobalt-Iron-Boron (Co—Fe—B) alloy;
the conductive annular layer includes one or more of Copper (Cu), copper alloy, Aluminum (Al), aluminum alloy, Ruthenium (Ru) or ruthenium alloy;
the annular tunnel insulator includes a Ruthenium (Ru) alloy; and
the planar reference magnetic layer includes a Cobalt-Iron-Boron (Co—Fe—B) alloy.
6 . The MTJ of claim 1 , wherein:
a magnetic field of the planar reference magnetic layer has a fixed polarization substantially perpendicular to a major planar orientation of the planar reference magnetic layer; and
a magnetic field of the annular free magnetic layer has a polarization substantially perpendicular to the major planar orientation of the planar reference magnetic layer and selectively switchable between being substantially parallel and substantially antiparallel to the magnetic field of the planar reference magnetic layer.
7 . The MTJ of claim 6 , wherein the magnetic field of the annular free magnetic layer is configured to switch to being substantially parallel to the magnetic field of the planar reference magnetic layer in response to a current flow in a first direction through the conductive annular layer and to switch to being substantially anti-parallel to the magnetic field of the planar reference magnetic layer in response to a current flow in a second direction through the conductive annular layer.
8 . A device comprising:
a plurality of annular structures, each annular structure including an annular non-magnetic layer disposed about an annular conductive layer, an annular free magnetic layer disposed about the annular non-magnetic layer, and an annular tunnel insulator disposed about the annular free magnetic layer;
a planar reference magnetic layer disposed about the plurality of annular structures and separated from the free magnetic layers by the annular tunnel barrier layers.
9 . The device of claim 8 , wherein each annular structure comprises a conical structure including a conical non-magnetic layer disposed about a conical portion of the conductive layer, a conical free magnetic layer disposed about the conical non-magnetic layer, and a conical tunnel barrier layer disposed about the conical free magnetic layer.
10 . The device of claim 9 , wherein each conical structure has a taper of approximately 10-45 degrees from a first side of the planar reference magnetic layer to a second side of the planar reference magnetic layer.
11 . The device of claim 8 , further comprising:
a first set of one or more additional layers disposed about the plurality of annular structures and on a first side of the planar reference magnetic layer; and
a second set of one or more additional layers disposed about the plurality of annular structures and on a second side of the planar reference magnetic layer.
12 . The device of claim 8 , further comprising:
the plurality of annular structures arranged in columns and rows; and
a plurality of insulator regions, each insulator region disposed in the planar reference magnetic layer between a respective pair of columns of the plurality of annular structures.
13 . The device of claim 8 , wherein
a magnetic field of the planar reference magnetic layer has a fixed polarization substantially perpendicular to a major planar orientation of the planar reference magnetic layer; and
a magnetic field of the annular free magnetic layer of each conical structure has a polarization substantially perpendicular to the major planar orientation of the planar reference magnetic layer and selectively switchable between being substantially parallel and substantially antiparallel to the magnetic field of the planar reference magnetic layer.
14 . The device of claim 13 , wherein the magnetic field of the annular free magnetic layer of each conical structure is configured to switch to being substantially parallel to the magnetic field of the planar reference layer in response to a current flow in a first direction through the conductive annular layer and to switch to being substantially anti-parallel to the magnetic field of the planar reference layer in response to a current flow in a second direction through the conductive annular layer.
15 . The device of claim 8 , wherein each annular structure and the portion of the planar reference magnetic layer proximately the respective annular structure comprises a Magnetic Tunnel Junction (MTJ) cell.
16 . A memory device comprising:
an array of Magnetic Tunnel Junction (MTJ) cells including:
a plurality of annular structures arranged in columns and rows, each annular structure including an annular non-magnetic layer disposed about an annular conductive layer, an annular free magnetic layer disposed about the annular non-magnetic layer, and an annular tunnel insulator disposed about the annular free magnetic layer; and
a planar reference magnetic layer disposed about the plurality of annular structures and separated from the free magnetic layers by the annular tunnel barrier layers;
a bit line coupled to the planar reference magnetic layer; and
a plurality of select transistors, each select transistor coupled to the annular conductive layer of a respective annular structure.
17 . The memory device of claim 16 , 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 of the plurality of annular structures; 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 of the plurality of annular structures.
18 . The memory device of claim 16 , further comprising:
a plurality of blocks of the array of MTJ cells arranged in columns and rows.
19 . The memory device of claim 18 , 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.
20 . The memory device of claim 16 , wherein
a magnetic field of the planar reference magnetic layer has a fixed polarization substantially perpendicular to a major planar orientation of the planar reference magnetic layer; and
a magnetic field of the annular free magnetic layer of each conical structure has a polarization substantially perpendicular to the major planar orientation of the planar reference magnetic layer and selectively switchable between being substantially parallel and substantially antiparallel to the magnetic field of the planar reference magnetic layer.
21 . The memory device of claim 20 , wherein the magnetic field of the annular free magnetic layer of each conical structure is configured to switch to being substantially parallel to the magnetic field of the planar reference magnetic layer in response to a current flow in a first direction through the conductive annular layer and to switch to being substantially anti-parallel to the magnetic field of the planar reference magnetic layer in response to a current flow in a second direction through the conductive annular layer.
22 . The memory device of claim 16 , further comprising:
the plurality of annular structures arranged in columns and rows in the array of MTJ cells; and
a plurality of insulator regions, each insulator region disposed in the planar reference magnetic layer between a respective pair of columns of the plurality of annular structures.