US 8,045,370 B2 · Memory self-reference read and write assist methods

Abstract

A magnetic tunnel junction memory apparatus and self-reference read and write assist schemes are described. One method of self-reference reading a magnetic tunnel junction memory unit includes applying a first read current through a magnetic tunnel junction data cell to form a first bit line read voltage, then applying a first magnetic field through the magnetic tunnel junction data cell forming a magnetic field modified magnetic tunnel junction data cell, and then applying a second read current thorough the magnetic field modified magnetic tunnel junction data cell to form a second bit line read voltage. The first read current being less than the second read current. Then comparing the first bit line read voltage with the second bit line read voltage to determine whether the magnetic tunnel junction data cell was in a high resistance state or a low resistance state. Methods of applying a magnetic field to the MTJ and then writing the desired resistance state are also disclosed.

Claims20

Dependent claims

A method of self-reference reading a magnetic tunnel junction memory unit, comprising:

applying a first read current through a magnetic tunnel junction data cell and forming a first bit line read voltage;
applying a first magnetic field through the magnetic tunnel junction data cell forming a magnetic field modified magnetic tunnel junction data cell;
applying a second read current thorough the magnetic field modified magnetic tunnel junction data cell and forming a second bit line read voltage, the first read current being less than the second read current;
and
comparing the first bit line read voltage with the second bit line read voltage to determine whether the magnetic tunnel junction data cell was in a high resistance state or a low resistance state.

2 more elements

A magnetic tunnel junction memory apparatus comprising:

a magnetic tunnel junction data cell, the magnetic tunnel junction data cell electrically between a bit line and a source line, the magnetic tunnel junction data cell is configured to switch between a high resistance state and a low resistance state by passing a polarized write current through the magnetic tunnel junction data cell;
an adjustable current driver electrically coupled to the bit line, the adjustable current driver configured to provide a provide a first read current and a second read current through the magnetic tunnel junction data cell;
a magnetic field generator adjacent to the magnetic tunnel junction data cell;
a first voltage storage device electrically coupled to the bit line and configured to store a first bit line voltage formed by the first read current;
a second voltage storage device electrically coupled to the bit line and configured to store a second bit line voltage formed by the second read current;
and
a differential sense amplifier electrically coupled to the first voltage storage device and electrically coupled to the second voltage storage device, the differential sense amplifier configured to compare the first bit line voltage with the second bit line voltage.

4 more elements

Dependencies are inferred from the claim text.

Memory self-reference read and write assist methods

Life of this patent

Memory self-reference read and write assist methods

Life of this patent

Abstract

Claims20