Patent ID: 7180113
Filing Date: 2007-02-20
Classification: G11C,H01L

Abstract:
1. A double-decker magnetoresistive random access memory (MRAM) cell comprising: a first magnetic tunnel junction including first and second magnetic regions made of magnetic material being stacked in a parallel, overlying relationship; a first tunneling barrier layer made of non-magnetic material separating the first and second magnetic regions; wherein the first magnetic region exhibits a first fixed magnetization adjacent the said first tunneling barrier layer, and wherein the second magnetic region exhibits a first free magnetization adjacent the first tunneling barrier layer that is free to be switched between the same and opposite directions with respect to the first fixed magnetization; a second magnetic tunnel junction including third and fourth magnetic regions made of magnetic material being stacked in a parallel, overlying relationship; a second tunneling barrier layer made of non-magnetic material separating the third and fourth magnetic regions; wherein the third magnetic region exhibits a second fixed magnetization adjacent the second tunneling barrier layer, and wherein the fourth magnetic region exhibits a second free magnetization adjacent the second tunneling barrier layer that is free to be switched between the same and opposite directions with respect to the second fixed magnetization; at least one pinning layer made of antiferromagnetic material pinning the first and second fixed magnetizations; first and second currents made to flow through first and second current lines, respectively carrying first and second currents, which generate magnetic fields that magnetically couple the free magnetizations of the first and second magnetic tunnel junctions; wherein the second and fourth magnetic regions are respectively comprised of a plurality of N ferromagnetic free layers which are antiferromagnetically coupled, where N is an integer greater than or equal to two; wherein the first and second fixed magnetizations are oriented in a same magnetic anisotropy axis and are inclined under an angle relative to at least one of the first and second free magnetizations; and wherein said first and second free magnetizations are inclined at an angle of 90 degrees.