Title :
Development of magnetic tunnel junction for toggle MRAM
Author :
Kim, H.-J. ; Oh, S.C. ; Bae, J.S. ; Nam, K.T. ; Lee, J.E. ; Park, S.O. ; Kim, H.S. ; Lee, N.I. ; Chung, U-in ; Moon, J.T. ; Kang, H.K.
Author_Institution :
Adv. Process Dev., Samsung Electron. Co., Ltd, Yongin-City, South Korea
Abstract :
Toggle switching mode MRAM is tested and characterized with respect to the free- and pinned-layer material and thickness. With magnetization curves, we were able to find the optimum thickness combinations of free-layer and spacer materials. For CoFeB where the intrinsic anisotropy field ( Hi) is about 20-30 Oe, one needs to have a reasonably high exchange coupling field (Hex) to ensure large switching margin. In case of an NiFe/Ru/NiFe free-layer, Hi is usually much smaller than Hex, so that further decrease of Hex between two magnetic layers is needed. The pinned-layer roughness and thickness are other factors to be optimized to reduce the toggle switching field. High cell aspect ratio ≥3.0 helps to minimize the switching distribution and enhance the switching stability.
Keywords :
magnetic anisotropy; magnetic storage; magnetic tunnelling; magnetisation reversal; random-access storage; MTJ; exchange coupling field; magnetic anisotropy field; magnetic layers; magnetic tunnel junction; magnetization curves; pinned-layer roughness; spacer materials; switching stability; toggle MRAM; Anisotropic magnetoresistance; Electrical resistance measurement; Electronic equipment testing; Magnetic anisotropy; Magnetic materials; Magnetic tunneling; Materials testing; Perpendicular magnetic anisotropy; Saturation magnetization; Stability; Exchange coupling field; magnetic anisotropy field; magnetic tunnel junction (MTJ); toggle MRAM;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2005.854935
