Magnetic Tunnel Junction Devices Including an Annular Free Magnetic Layer and a Planar Reference Magnetic Layer

A device comprising:

• a first 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;
• and
• a first planar reference magnetic layer disposed about the first plurality of annular structures and separated from the free magnetic layers by the annular tunnel barrier layers, wherein;
• a magnetic field of the first planar reference magnetic layer has a fixed polarization substantially parallel to a major planar orientation of the first planar reference magnetic layer;
• and
• a magnetic field of the annular free magnetic layer of each annular structure has a polarization substantially parallel to the major planar orientation of the first planar reference magnetic layer and selectively switchable between being substantially parallel and substantially antiparallel to the magnetic field of the first planar reference magnetic layer.

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, wherein;
• a magnetic field of the planar reference magnetic layer has a fixed polarization substantially parallel to a major planar orientation of the planar reference magnetic layer;
• and
• a magnetic field of the annular free magnetic layer of each annular structure has a polarization substantially parallel 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;
• 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.

A method of manufacturing a Magnetic Tunnel Junction (MTJ) comprising:

• forming a first planar non-magnetic insulator layer;
• forming a planar reference magnetic layer on the first planar non-magnetic insulator layer, wherein a magnetic field of the planar reference magnetic layer has a fixed polarization substantially parallel to a major planar orientation of the planar reference magnetic layer;
• forming a second planar non-magnetic insulator layer on the planar reference magnetic layer;
• forming one or more annular openings through the second planar non-magnetic insulator layer, the planar reference magnetic layer and the first planar non-magnetic insulator layer;
• forming an annular tunnel insulator on the walls of the one or more annular openings;
• forming an annular free magnetic layer on the annular insulator inside the one or more annular openings, wherein a magnetic field of the annular free magnetic layer has a polarization substantially parallel 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 layer;
• forming an annular non-magnetic layer on the annular free magnetic layer inside the one or more annular openings;
• and
• forming an annular conductive core inside the annular non-magnetic layer in the one or more annular openings.