The influence of the mixed inert gas species for plasma oxidization process of a metallic Al layer on the tunnel magnetoresistance (TMR) was investigated for a magnetic tunnel junction (MTJ), Ta50Å/Cu200Å/Ta200Å/Ni- Fe50Å/Cu50Å/Mn75Ir25100Å/Co 70Fe3025Å/Al-O/Co70Fe 3025Å/Ni-Fe100Å/Cu200Å/Ta50Å. Using Kr-O 2 plasma, a 58.8% of TMR ratio was obtained at room temperature after annealing the junction at 300°C, while the achieved TMR ratio of the MTJ fabricated with usual Ar-O2 plasma remained 48.6%. A faster oxidization rate of the Al layer by using Kr-O2 plasma is a possible cause to prevent the over oxidization of the Al layer, which depolarizes the surface of the underlaid ferromagnetic electrode, and to realize a large magnetoresistance.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)