MAGNETIC TUNNEL JUNCTION (MTJ) AND METHODS, AND MAGNETIC RANDOM ACCESS MEMORY (MRAM) EMPLOYING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide magnetic tunnel junctions (MTJs) and methods of forming the same.SOLUTION: A pinned layer is disposed in an MTJ such that a free layer of the MTJ can be coupled to a drain of an access transistor when provided in a magnetic random access memory (MRAM) bit cell. This structure alters the write current flow direction to align the write current characteristics of the MTJ with write current supply capability of an MRAM bit cell employing the MTJ. As a result, more write current can be provided to switch the MTJ from a parallel (P) state to an anti-parallel (AP) state. An anti-ferromagnetic material (AFM) layer is provided on the pinned layer to fix pinned layer magnetization. To provide enough area for depositing the AFM layer to secure pinned layer magnetization, a pinned layer having a pinned layer surface area greater than a free layer surface area of the free layer is provided.