Method and system for providing a magnetic junction usable in spin transfer torque applications using multiple stack depositions

A method for providing a plurality of magnetic junctions, each of the plurality of magnetic junctions including a pinned layer, a free layer and a nonmagnetic tunneling barrier layer between the pinned layer and the free layer, the method comprising:

• providing a first plurality of layers for the plurality of magnetic junctions, the first plurality of layers including a magnetic layer for the free layer and an Mg layer on the magnetic layer;
• providing a carbon hard mask on the Mg layer, the carbon hard mask covering a first portion of the first plurality of layers corresponding to the plurality of magnetic junctions, the carbon hard mask including at least one aperture exposing a second portion of the first plurality of layers corresponding to at least one spacing between the plurality of magnetic junctions, the at least one spacing being not more than fifty nanometers;
• ion beam etching the second portion of the first plurality of layers, a remaining portion of the first plurality of layers forming a first portion of each of the plurality of magnetic junctions, the first portion including the free layer, the free layer for each the plurality of magnetic junctions being at the at least one spacing;
• providing an insulating refill between the first portion of each of the plurality of magnetic junctions;
• removing the carbon hard mask using an oxygen reactive ion etch, the oxygen reactive ion etch oxidizing the Mg layer to provide an MgO layer, the MgO layer forming at least a portion of the nonmagnetic tunneling barrier layer;
• providing a second plurality of layers forming a second portion of the stack for the plurality of magnetic junctions, the second plurality of layers including an additional magnetic layer for a pinned layer for each of the plurality of magnetic junctions.