Perpendicular magnetic anisotropy in Ta/CoFeB/MgO systems synthesized on treated SiN/SiO2 substrates for magnetic memories

Ta(5 nm)/CoFeB(1 nm)/MgO(2 nm) stacks have been deposited by magnetron sputtering on top of 8" Si/SiN/SiO2 substrates, where the effects of different passivation steps related to copper damascene processes have been simulated. It is shown that excellent thickness uniformity of the deposited stack is achieved on 8" areas, and strong uniaxial perpendicular magnetic anisotropy Ku up to 0.5–1 × 106 J/m3 develops in the 1 nm CoFeB following thermal annealing at 300 °C for 2 h, irrespective of the adopted passivation treatment. The CoFeB coercive field varies from 0.21 to 0.51 kA/m for substrate surface roughness in the range of 0.45–0.55 nm. These results are of relevance in the view of integrating into standard complementary metal-oxide semiconductor process, advanced magnetic memory concepts based on perpendicular magnetic anisotropy in ultrathin layers.

► Growth of Ta/CoFeB/MgO showing perpendicular magnetic anisotropy (PMA) on 8" area
► Influence of different copper damascene processes on stacks properties
► Excellent uniformity (layer thicknesses and interfacial roughness) on 8" areas
► Strong PMA achieved on 8" areas following thermal annealing
► CMOS compatibility of PMA systems based on CoFeB