Patent ID: 7813168
Filing Date: 2010-10-12
Classification: G11C

Abstract:
1. A method of self-reference reading a spin-transfer torque memory unit, comprising: applying a first read current through a magnetic tunnel junction data cell and forming a first bit line read voltage, the magnetic tunnel junction data cell having a first resistance state, the magnetic tunnel junction comprising a free magnetic layer having a free magnetization orientation and a reference magnetic layer having a reference magnetization orientation, the magnetic tunnel junction data cell having a first energy barrier value required to switch the magnetic tunnel junction data cell between a high resistance state and a low resistance state; storing the first bit line read voltage in a first voltage storage device; applying a first magnetic field through the magnetic tunnel junction data cell forming a magnetic field modified magnetic tunnel junction data cell, the magnetic field being parallel or anti-parallel with the magnetization orientation of the reference magnetic layer, the magnetic field modified magnetic tunnel junction data cell having a second energy barrier value being greater than the first energy barrier value; applying a second read current thorough the magnetic field modified magnetic tunnel junction data cell having the first resistance state and forming a second bit line read voltage, the first read current being less than the second read current; storing the second bit line read voltage in a second voltage storage device; and comparing the stored first bit line read voltage with the stored second bit line read voltage to determine whether the first resistance state of the magnetic tunnel junction data cell was a high resistance state or low resistance state.