Local thermal enhancement of magnetic memory cell during programming
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorDenny Duan-Lee Tang
Life of this patent
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Abstract
A problem associated with the programming of MRAM (magnetic random access memory) has been that the required current is orders of magnitude larger than that needed for many other memory devices such as SRAMs or DRAMs. This problem has been overcome by adding heating lines to the standard array configuration. These lines provide local heating sources located in close proximity to the memory elements so that when a given element is being programmed it is also being heated. The effect of the heating is to lower the threshold for magnetization so that a lower field (and hence reduced program current) can be used. It is also possible to make the base layer of the memory element itself serve as the heating element.
Claims38
An array of magnetic memory elements, comprising:
- a heating line, having a width and a thickness, that includes local heating elements each such heating element being located in close proximity to one of said memory elements;
- and
- a programming line that passes near a memory element.
An array of magnetic memory elements, each memory element having a base layer, comprising:
- a bit line and a programming line, having a width and a thickness, whereby individual memory elements in said array may be addressed wherever said bit and programming lines intersect;
- said programming line being disposed to connect the memory elements, whereby the base layer of each memory element is a part of said programming line;
- and
- the resistance of the base layers being larger, relative to other parts of said programming line, whereby each base layer of each memory element is a heating element.
A magnetic memory, comprising:
- an array of magnetic tunnel junction memory elements, each such memory element including a base layer having a first width;
- a programming line, having a second width that is greater than said first width, that connects the memory elements, whereby the base layer of each memory element is part of said programming line and, by virtue of its reduced width, is a local source of joule heat;
- and
- circuitry for selecting a single memory element of said array.
A process for programming a magnetic memory element, comprising:
- providing an array of magnetic memory elements;
- providing a heating line, having a width and a thickness, that includes local heating elements each such heating element being located in close proximity to one of said memory elements;
- providing a programming line that passes near a memory element;
- passing a first current through said heating line whereby a memory element is heated, thereby reducing said memory element's threshold field for magnetization;
- passing a second current through said programming line, said second current being sufficient to generate said reduced threshold field, whereby said memory element is magnetized and a bit of information is stored therein.
A process for programming a magnetic memory element, comprising:
- providing an array of magnetic memory elements, each such memory element having a base layer;
- providing a bit line and a programming line, having a width and a thickness, whereby individual memory elements in said array may be addressed wherever said bit and programming lines intersect;
- disposing said programming line to connect the memory elements, whereby the base layer of each memory element is a part of said programming line;
- increasing the resistance of the base layers relative to all other parts of said programming line whereby each base layer of a memory element becomes a local source of heat;
- passing a first current through said programming line thereby generating a first magnetic field and whereby all base layers on said programming line heat their associated memory elements, thereby reducing said memory elements' threshold field for magnetization to a value;
- passing a second current through said bit line, thereby generating a second magnetic field, the combination of said first and second magnetic fields being sufficient to exceed said reduced threshold field value, whereby said memory element is magnetized and a bit of information is stored therein.
A process for programming a magnetic tunnel junction, comprising:
- providing an array of magnetic tunnel junction memory elements, each such memory element including a base layer having a first width;
- providing a programming line, having a second width that is greater than said first width, that connects the memory elements, whereby the base layer of each memory element is part of said programming line and, by virtue of its reduced width, is a local source of joule heat;
- selecting a single memory element of said array and then passing a current through said programming line whereby only said selected memory element is heated, thereby reducing said memory element's threshold field for magnetization;
- and
- said current also being sufficient to generate said reduced threshold field, magnetizing said memory element and storing therein a bit of information.
Dependencies are inferred from the claim text.