US 6,777,730 B2 · Antiparallel magnetoresistive memory cells

Abstract

A ferromagnetic thin-film based digital memory having a plurality of bit structures electrically interconnected with information storage and retrieval circuitry that avoids information loss in one bit structure because of operating the others through this circuitry. Each of these bit structures formed of a relative orientation maintenance intermediate layer having two major surfaces on opposite sides thereof with a pair of memory films of an anisotropic ferromagnetic material each on a corresponding one of said relative orientation maintenance intermediate layer major surfaces. The relative orientation maintenance intermediate layer is of a material and a selected thickness so as to maintain magnetizations of said memory films oriented in substantially opposite directions. Interconnection electrodes pairs are each in electrically conductive contact with a corresponding one of the bit structures on substantially opposite sides thereof near or at substantially opposite edges of the relative orientation maintenance intermediate layer major surface. A magnetization reference direction layer able to maintain relatively well its magnetization orientation can be provided across a nonmagnetic layer from one of the pair of memory films with the nonmagnetic layer being either electrically conductive or insulative.

Claims68

Dependent claims

A ferromagnetic thin-film based digital memory, said memory comprising:

a plurality of bit structures electrically interconnected with information storage and retrieval circuitry, said bit structures comprising:
a relative orientation maintenance intermediate layer having two major surfaces on opposite sides thereof;
and
a pair of memory films of an anisotropic ferromagnetic material each on a corresponding one of said relative orientation maintenance intermediate layer major surfaces, said relative orientation maintenance intermediate layer being of a material and a selected thickness so as to maintain magnetizations of said memory films oriented in substantially opposite directions, said pair of memory films having sufficiently similar magnetic moments so as to substantially maintain magnetization orientations thereof despite magnetic fields occurring thereabout due to changes of magnetizations orientations of those said pairs of memory films in other said bit structures in said plurality thereof under direction of said information storage and retrieval circuitry;
and
interconnection electrodes having pairs thereof each in electrically conductive contact with a corresponding one of said bit structures with members in a said interconnection electrode pair contacting a corresponding bit structure being spaced apart from one another and each near or at edges of a said relative orientation maintenance intermediate layer major surface with at least one member of a said interconnection electrode pair being electrically coupled to said information storage and retrieval circuitry.

3 more elements

A ferromagnetic thin-film based digital memory, said memory comprising:

a plurality of bit structures electrically interconnected with information storage and retrieval circuitry, said bit structures comprising:
a relative orientation maintenance intermediate layer having two major surfaces on opposite sides thereof,
a pair of memory films of an anisotropic ferromagnetic material each on a corresponding one of said relative orientation maintenance intermediate layer major surfaces, said relative orientation maintenance intermediate layer being of a material and a selected thickness so as to maintain magnetizations of said memory films oriented in substantially opposite directions, said pair of memory films having sufficiently similar magnetic moments so as to substantially maintain magnetization orientations thereof despite magnetic fields occurring thereabout due to changes of magnetizations orientations of those said pairs of memory films in other said bit structures in said plurality thereof under direction of said information storage and retrieval circuitry;
a nonmagnetic intermediate layer of an electrically conductive material on one of said pair of memory films and across that said memory film from one of said relative orientation maintenance intermediate layer major surfaces with said nonmagnetic intermediate layer having a major surface on a side thereof opposite said pair of memory films;
and
a magnetization reference layer on said major surface of said nonmagnetic intermediate layer having a substantially fixed magnetization direction;
and
interconnection electrodes having pairs thereof each in electrically conductive contact with a corresponding one of said bit structures with members in a said interconnection electrode pair contacting a corresponding bit structure being spaced apart from one another and each near or at edges of a said relative orientation maintenance intermediate layer major surface with at least one member of a said interconnection electrode pair being electrically coupled to said information storage and retrieval circuitry.

5 more elements

A ferromagnetic thin-film based digital memory, said memory comprising:

a plurality of bit structures electrically interconnected with information storage and retrieval circuitry, said bit structures comprising:
a relative orientation maintenance intermediate layer having two major surfaces on opposite sides thereof;
and
a memory film of an anisotropic ferromagnetic material on each of said relative orientation maintenance intermediate layer major surfaces, said relative orientation maintenance intermediate layer being of a material and a selected thickness so as to maintain magnetizations of said memory film, adjacent each of said intermediate layer major surfaces, oriented in substantially opposite directions;
a nonmagnetic intermediate layer of an electrically insulative material on said memory film across from one of said relative orientation maintenance intermediate layer major surfaces with said nonmagnetic intermediate layer having a major surface on a side thereof opposite said memory film;
and
a magnetization reference layer on said major surface of said nonmagnetic intermediate layer having a substantially fixed magnetization direction;
and
interconnection electrodes having pairs thereof each in electrically conductive contact with a corresponding one of said bit structures with members in a said interconnection electrode pair contacting a corresponding bit structure being spaced apart from one another and each near or at edges of a said relative orientation maintenance intermediate layer major surface with at least one member of a said interconnection electrode pair being electrically coupled to said information storage and retrieval circuitry.

6 more elements

A ferromagnetic thin-film based digital memory, said memory comprising:

a plurality of bit structures electrically interconnected with information storage and retrieval circuitry, said bit structures comprising:
a relative orientation maintenance intermediate layer having two major surfaces on opposite sides thereof;
a pair of memory films of an anisotropic ferromagnetic material each on a corresponding one of said relative orientation maintenance intermediate layer major surfaces, said relative orientation maintenance intermediate layer being of a material and a selected thickness so as to maintain magnetizations of said memory films oriented in substantially opposite directions, said pair of memory films having sufficiently similar magnetic moments so as to substantially maintain magnetization orientations thereof despite magnetic fields occurring thereabout due to changes of magnetizations orientations of those said pairs of memory films in other said bit structures in said plurality thereof under direction of said information storage and retrieval circuitry;
a nonmagnetic intermediate layer of a nonmagnetic material on one of said pair of memory films and across that said memory film from one of said relative orientation maintenance intermediate layer major surfaces with said nonmagnetic intermediate layer having a major surface on a side thereof opposite said pair of memory films;
and
a magnetization reference layer on said major surface of said nonmagnetic intermediate layer having a substantially fixed magnetization direction;
interconnection electrodes having at least pairs thereof each in electrically conductive contact with a corresponding one of said bit structures with members in a said interconnection electrode pair contacting a corresponding said bit structure being spaced apart from one another such that at least one said member of a said interconnection electrode pair is near or at an edge of a said relative orientation maintenance intermediate layer major surface;
and
a plurality of transistors electrically interconnected in said information storage and retrieval circuitry so that a said bit structure has a transistor in said plurality of transistors electrically coupled thereto at least in part by a member in that said interconnection electrode pair contacting that said bit structure so that said transistor selectively substantially prevents current in at least one direction through that said member and said bit structure.

6 more elements

Dependencies are inferred from the claim text.

Antiparallel magnetoresistive memory cells

Life of this patent

Antiparallel magnetoresistive memory cells

Life of this patent

Abstract

Claims68