Methods for forming structures with desired crystallinity for MRAM applications

A method of forming a magnetic tunnel junction structure on a substrate, comprising:

• patterning a film stack having a tunneling barrier layer disposed between a magnetic reference layer and a magnetic storage layer disposed on a substrate to remove a portion of the film stack from the substrate until an upper surface of the substrate is exposed, wherein the magnetic storage layer comprises a first magnetic storage sublayer, a second magnetic storage sublayer and a metallic intermediate layer therebetween;
• forming a sidewall passivation layer comprising carbon containing materials or nitrogen containing materials on sidewalls of the patterned film stack, the sidewall passivation layer having a vertical portion coplanar along a vertical axis normal to a major axis of the substrate and a horizontal portion extending outwardly from the vertical portion along the substrate such that the horizontal portion covers the upper surface of the substrate where the portion of the film stack was removed during patterning;
• and
• subsequently performing a thermal annealing process to the film stack
• wherein the film stack further comprises a pinning layer disposed between the substrate and the magnetic reference layer, the pinning layer further comprising sequentially from the magnetic reference layer in the direction of the substrate;
• a Co layer, a Co/Pt layer, an Ru layer, a Co layer, a Co/Pt layer, a Pt layer, a Ta layer, an Ru layer, a Ta layer, and a TaN layer.

A method of forming a magnetic tunnel junction structure on a substrate, comprising:

• patterning a film stack having a tunneling barrier layer disposed between a magnetic reference layer and a magnetic storage layer disposed on a substrate to remove a portion of the film stack from the substrate until an upper surface of the substrate is exposed, wherein the magnetic storage layer comprises a first magnetic storage sublayer, a second magnetic storage sublayer and a metallic intermediate layer therebetween;
• forming a sidewall passivation layer on sidewalls of the patterned film stack, the sidewall passivation layer having a vertical portion coplanar along a vertical axis normal to a major axis of the substrate and a horizontal portion extending outwardly from the vertical portion along the substrate such that the sidewall passivation layer covers the top surface of the substrate;
• forming an insulation layer comprising silicon oxide, where the portion of the film stack was removed during patterning, that is in direct contact with the sidewall passivation layer on the substrate such that the horizontal portion is between the insulation layer and the substrate such that the insulation layer does not contact the top surface of the substrate;
• and
• driving dopants from the magnetic reference layer and the magnetic storage layer laterally outward into the sidewall passivation layer by a thermal treatment process
• wherein the film stack further comprises a pinning layer disposed between the substrate and the magnetic reference layer, the pinning layer further comprising sequentially from the magnetic reference layer in the direction of the substrate;
• a Co layer a Co/Pt layer, an Ru layer, a Co layer, a Co/Pt layer, a Pt layer, a Ta layer, an Ru layer, a Ta layer, and a TaN layer.