Method for fabricating MRAM bits on a tight pitch

A method for fabricating a magnetoresistive random access memory (MRAM) device, comprising:

• etching a pattern of first columns into a hardmask layer disposed on a magnetic tunnel junction (MTJ) stack that is disposed on a substrate having one or more electrically conductive contacts, wherein the MTJ stack comprises a tunnel barrier layer between first and second ferromagnetic layers, wherein the second ferromagnetic layer is disposed on and in contact with the one or more electrically conductive contacts and the substrate, and wherein the pattern of first columns is aligned to the one or more electrically conductive contacts, wherein the hardmask layer is disposed on and in contact with the first ferromagnetic layer;
• etching the first ferromagnetic layer to expose the tunnel barrier layer and to form second columns comprising the hardmask layer and the first ferromagnetic layer;
• forming a passivation layer on the exposed tunnel barrier layer and on top surfaces and side surfaces of the first columns;
• and
• etching the passivation layer on the exposed tunnel barrier layer, the exposed tunnel barrier layer, and the second ferromagnetic layer to form third columns comprising the hardmask layer, the first ferromagnetic layer, the tunnel barrier layer, and the second ferromagnetic layer.