Multi-level memory cell using multiple magnetic tunnel junctions with varying MGO thickness

摘要

A Multi-Level Memory Cell (MLC) using multiple Magnetic Tunnel Junction (MTJ) structures having one or more layers with varying thickness is disclosed. The multiple MTJ structures, which are vertically stacked and arranged in series, may have substantially identical area dimensions to minimize fabrication costs because one mask can be used to pattern the multiple MTJ structures. Further, varying the thicknesses associated with the one or more layers may provide the multiple MTJ structures with different switching current densities and thereby increase memory density and improve read and write operations. In one embodiment, the layers with the varying thicknesses may include tunnel barriers or magnesium oxide layers associated with the multiple MTJ structures and/or free layers associated with the multiple MTJ structures.