Magnetic random access memory designs with controlled magnetic switching mechanism
AssigneeHeadway Technologies, Inc.
InventorsTai Min, Po Kang Wang
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Abstract
An MRAM array is formed of MTJ cells shaped so as to have their narrowest dimension at the middle of the cell. A preferred embodiment forms the cell into the shape of a kidney or a peanut. Such a shape provides each cell with an artificial nucleation site at the narrowest dimension, where an applied switching field can switch the magnetization of the cell in manner that is both efficient and uniform manner across the array.
Claims3
A method for fabricating a magnetic tunnel junction (MTJ) cell, said cell having a narrow dimension at its middle whereat artificial nucleation sites for magnetization switching are formed and said cell having an easy axis of magnetization passing longitudinally through said middle, thereby producing a fanning mode of magnetization vectors at opposite peripheral edges of said cell and, as a result, said cell having a lowered switching field threshold and a reduced sensitivity to defects and shape irregularities comprising:
- forming an MTJ layered stack, the magnetic layers of said stack having a common crystalline anisotropy and common easy axis of magnetization;
- patterning within said stack, by photolithography and ion-milling methods, at least one MTJ cell having a narrow dimension at its middle, said dimension being transverse to the direction of said easy axis of magnetization.
Dependencies are inferred from the claim text.