Patent ID: 8450119

Claim:
A patterned MRAM MTJ cell comprising: an MTJ stack, said stack including an upper ferromagnetic free layer, a lower ferromagnetic pinned layer and a tunneling barrier layer formed therebetween; a single bilayer capping and masking layer formed on said upper ferromagnetic free layer of said MTJ stack, said single bilayer comprising: a capping layer of Ta formed to a thickness between 200 and 400 angstroms on said ferromagnetic free layer, said Ta layer being substantially free of oxidation; a masking layer of TaN formed to a thickness between 100 and 200 angstroms on top of said layer of Ta; wherein said single bilayer capping and masking layer are patterned and said MTJ stack is conformally patterned by said patterned single bilayer capping and masking layer and wherein said TaN layer protects said Ta capping layer and provides improved adhesion to contiguous dielectric materials; whereby a layer of dielectric material formed surrounding said MTJ cell is rendered smooth and coplanar and well bonded to an upper surface of said TaN layer as a result of said improved adhesion properties.