Improved TMR on CoFeB/MgO/CoFeB p-MTJ on textured TiN buffer layer integrated on Si substrate

Abstract

In this study, a highly texture-driven CoFeB/MgO/CoFeB magnetic tunnel junction (MTJ) system is realized using a textured TiN seed layer on industrial standard silicon wafers. The textured MTJ exhibited a tunnel magnetoresistance of 91%, approximately equivalent to a threefold improvement compared to the semi-amorphous reference. Additionally, influenced by the texture quality of the TiN seed layer and the W buffer layer, the crystallinity of the CoFeB free layer was improved and the W/CoFeB surface was smoothened. Hence, the coercivity of the CoFeB free layer was reduced to 0.25 mT, in comparison to 7.32 mT in the amorphous system. The textured free layer also achieved a lower Gilbert damping constant by 11% and an enhanced perpendicular magnetic anisotropy, with an anisotropy energy density of (7.9 ± 0.1)×105 J/m3 compared to (6.7 ± 0.1)×105 J/m3 for the semi-amorphous reference.