Haynes and Boone, LLP
High thermal stability by doping of oxide capping layer for spin torque transfer (STT) magnetic random access memory (MRAM) applications
A magnetic tunnel junction (MTJ) is disclosed wherein a free layer (FL) interfaces with a metal oxide (Mox) layer and a tunnel barrier layer to produce interfacial perpendicular magnetic anisotropy (PMA). The Mox layer has a non-stoichiometric oxidation state to minimize parasitic resistance, and comprises a dopant to fill vacant lattice sites thereby blocking oxygen diffusion through the Mox layer to preserve interfacial PMA and high thermal stability at process temperatures up to 400° C. Various methods of forming the doped Mox layer include deposition of the M layer in a reactive environment of O2 and dopant species in gas form, exposing a metal oxide layer to dopant species in gas form, and ion implanting the dopant. In another embodiment, where the dopant is N, a metal nitride layer is formed on a metal oxide layer, and then an anneal step drives nitrogen into vacant sites in the metal oxide lattice.
TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD.
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inventional inventional inventional
Yuan-Jen Ru-Ying Jodi Mari Jian Huanlong Guenole
Lee Tong Iwata Zhu Lui Jan