Ultra-high thermal stability of perpendicular magnetic anisotropy in the W buffered CoFeB/MgO stacks with Zr dusting layers

Practical device applications of magnetic multilayers with perpendicular magnetic anisotropy (PMA) usually need to match the mature complementary metal-oxide-semiconductor (CMOS) integrated techniques, which require high temperature annealing during the back-end-of-line process. Here, we report the realization of PMA in the W buffered CoFeB/MgO stack by inserting a thin Zr dusting layer between CoFeB and MgO layers. An ultra-high thermal stability of PMA in the W/CoFeB/Zr/MgO stack is observed, which is robust upon annealing at 600 °C. The establishment of PMA in W/CoFeB/Zr/MgO is due to the formation of an interface layer between CoFeB and MgO doped with oxidized Zr. After annealing at 540 °C, the magnetic interfacial anisotropy density reaches 3.08 erg/cm², which is much higher than those in previous reports. The results suggest that the W/CoFeB/Zr/MgO stack with extra high annealing stability is a potential candidate to achieving the practical application of spin-logic device that is compatible with the mature CMOS integrated techniques.