# US 7,613,035 B2 · Magnetic memory device and method of writing into the same

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- Number: US 7,613,035 B2
- Document ID: US7613035B2
- Status: Granted
- Kind: B2
- Application number: 12/135,529
- Filed: 2008-06-09
- Published: 2008-10-02
- Granted: 2009-11-03
- Earliest claimed: 2005-12-09
- Assignees: Fujitsu Limited
- Inventors: Masaki Aoki
- Web page: https://patentgrep.com/patent/US7613035B2

## CPC

- H10B 61/22: {of the field-effect transistor [FET] type}
- B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
- G11C 11/1655: {Bit-line or column circuits}
- G11C 11/1657: {Word-line or row circuits}
- G11C 11/1659: {Cell access}
- G11C 11/1673: {Reading or sensing circuits or methods}
- G11C 11/1675: {Writing or programming circuits or methods}
- H10B: ELECTRONIC MEMORY DEVICES
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

A magnetic memory device includes a memory cell including magnetoresistance effect elements MTJ1, MTJ2 and a select transistor connected to the connection node of the magnetoresistance effect elements MTJ1, MTJ2, a first signal line extended in a first direction and connected to the magnetoresistance effect element MTJ1, a second signal line extended in the first direction and connected to the magnetoresistance effect element MTJ2, and a third signal line extended in a second direction and crossing the first signal line in a region where the magnetoresistance effect element MTJ1 is formed and crossing the second signal line in a region where the magnetoresistance effect element MTJ2 is formed. When memory information is written into the memory cell, the memory information to be memorized is switched by directions of write currents to be flowed to the first and the second signal lines.

## Claims

### Claim 1

A method of writing into a magnetic memory device comprising:
flowing a first write current to a first signal line;
flowing a second write current to a second signal line, the second write current being directed opposite to the first write current;
flowing a third write current to a third signal line; and
memorizing a first memory information or a second memory information, based on directions of the first write current and the second write current,
wherein the magnetic memory device including a memory cell including a first magnetoresistance effect element, a second magnetoresistance effect element having one terminal connected to one terminal of the first magnetoresistance effect element, and a select transistor connected to a connection node of the first magnetoresistance effect element and the second magnetoresistance effect element; the first signal line extended in a first direction and connected to the other end of the first magnetoresistance effect element; the second signal line extended in the first direction and connected to the other end of the second magnetoresistance effect element; and the third signal line extended in a second direction crossing the first direction, crossing the first signal line in a region where the first magnetoresistance effect element is formed, and crossing the second signal line in the region where the second magnetoresistance effect element is formed, wherein the magnetic memory device memorizes the first memory information with the first magnetoresistance effect element being in a high resistance state and the second magnetoresistance effect element being in a lower resistance state or the second memory information with the first magnetoresistance effect element being in the lower resistance state and the second magnetoresistance effect element being in the high resistance state.

### Claim 2

A method of writing into a magnetic memory device comprising:
when a first memory information is written into a memory cell, a first write current is flowed to a first signal line, a second write current being directed opposite to the first write current is flowed to a second signal line, and a third write current is flowed to a third signal line to apply to a first magnetoresistance effect element a synthetic magnetic field of a magnetic field generated by the first write current and a magnetic field generated by the third write current and apply to a second magnetoresistance effect element a synthetic magnetic field of a magnetic field generated by the second write current and a magnetic field generated by the third write current, and
when a second memory information is written in the memory cell, a fourth write current which is directed opposite to the first write current is flowed to the first signal line, a fifth write current of the same direction as the first write current is flowed to the second signal line, a sixth write current of the same direction as the third write current is flowed to the third signal line to apply the first magnetoresistance effect element a synthetic magnetic field of a magnetic field generated by the fourth write current and a magnetic field generated by the sixth write current and apply to the second magnetoresistance effect element a synthetic magnetic field of a magnetic field generated by the fifth write current and a magnetic field generated by the sixth write current,
wherein the magnetic memory device including the memory cell including the first magnetoresistance effect element, the second magnetoresistance effect element having one terminal connected to one terminal of the first magnetoresistance effect element, and a select transistor connected to a connection node of the first magnetoresistance effect element and the second magnetoresistance effect element; the first signal line extended in a first direction and connected to the other end of the first magnetoresistance effect element; the second signal line extended in the first direction and connected to the other end of the second magnetoresistance effect element; and the third signal line extended in a second direction crossing the first direction, crossing the first signal line in a region where the first magnetoresistance effect element is formed, and crossing the second signal line in the region where the second magnetoresistance effect element is formed, wherein the magnetic memory device memorizes the first memory information with the first magnetoresistance effect element being in a high resistance state and the second magnetoresistance effect element being in a lower resistance state or the second memory information with the first magnetoresistance effect element being in the lower resistance state and the second magnetoresistance effect element being in the high resistance state.

### Claim 3 (depends on 2)

The method of writing into a magnetic memory device according to claim 2, wherein
the magnetic memory device including a plurality of said memory cells, and a plurality of said first signal lines and a plurality of said second signal lines which are respectively connected to said respective plural memory cells, and
for said respective plurality of memory cells, directions of said write currents to be flowed to the first signal lines and the second signal lines are set discretely corresponding to information-to-be-memorized to be written to thereby write simultaneously into said respective plurality of memory cells.

### Claim 4 (depends on 3)

The method of writing into a magnetic memory device according to claim 3, wherein
the magnetic memory device further includes a first current source disposed on a side of one ends of the first signal line and the second signal line, and a second current source disposed on a side of the other ends of the first signal lines and the second signal lines,
said first write current or the fifth write current is supplied from the first current source, and the second write current or the fourth write current is supplied from the second current source.

### Claim 5 (depends on 3)

The method of writing into a magnetic memory device according to claim 3, wherein
the magnetic memory device further includes a current source disposed on a side of one ends of the first signal line and the second signal line, and a switching element disposed on a side of the other ends of the first signal line and the second signal line, for electrically connecting or disconnecting the first signal line and the second signal line, and
when a memory information is written, the first signal line and the second signal line are electrically connected to each other by the switching element to form a current path of the first signal line and the second signal line connected to each other and supply the write current from the current source to the current path of the first signal line and the second signal line.

### Claim 6 (depends on 3)

The method of writing into a magnetic memory device according to claim 3, wherein
the magnetic memory device further includes a current source disposed on a side of one ends of the first signal line and the second signal line, and a switching element disposed on a side of the other ends of the first signal lines and the second signal lines, for electrically connecting or disconnecting the first signal line and the second signal line, and
when a memory information is written, the first signal line and the second signal line are electrically connected to each other by the switching element to form a current path of the first signal line and the second signal line connected to each other and supply the write current from the current source to the current path to the first signal line and the second signal line.

### Claim 7 (depends on 2)

The method of writing into a magnetic memory device according to claim 2, wherein
the magnetic memory device further includes a first current source disposed on a side of one ends of the first signal line and the second signal line, and a second current source disposed on a side of the other ends of the first signal lines and the second signal lines,
said first write current or the fifth write current is supplied from the first current source, and the second write current or the fourth write current is supplied from the second current source.

### Claim 8 (depends on 2)

The method of writing into a magnetic memory device according to claim 2, wherein
the magnetic memory device further includes a current source disposed on a side of one ends of the first signal line and the second signal line, and a switching element disposed on a side of the other ends of the first signal line and the second signal line, for electrically connecting or disconnecting the first signal line and the second signal line, and
when a memory information is written, the first signal line and the second signal line are electrically connected to each other by the switching element to form a current path of the first signal line and the second signal line connected to each other and supply the write current from the current source to the current path of the first signal line and the second signal line.

### Claim 9

A magnetic memory device comprising:
a memory cell including a first magnetoresistance effect element, a second magnetoresistance effect element having one terminal connected to one terminal of the first magnetoresistance effect element, and a select transistor connected to a connection node of the first magnetoresistance effect element and the second magnetoresistance effect element;
a first signal line extended in a first direction and connected to the other end of the first magnetoresistance effect element;
a second signal line extended in the first direction and connected to the other end of the second magnetoresistance effect element;
a third signal line extended in a second direction crossing the first direction, crossing the first signal line in a region where the first magnetoresistance effect element is formed, and crossing the second signal line in the region where the second magnetoresistance effect element is formed,
a fourth signal line extended in the first direction and connected to the connection node of the memory cell via the select transistor; and
another memory cell formed adjacent to said memory cell in the first direction, wherein
the select transistors of said memory cell and said another memory cell are formed in one active region, and a contact connecting the select transistors of said memory cell and said another memory cells to the fourth signal line are in common.

### Claim 10 (depends on 9)

The magnetic memory device according to claim 9, wherein
the active region has a rectangular shape elongated in the first direction.

### Claim 11 (depends on 9)

The magnetic memory device according to claim 9, wherein
the active region has a V-shape bent in the second direction.

### Claim 12 (depends on 9)

The magnetic memory device according to claim 9, further comprising:
a drive circuit for writing memory information into the memory cell, wherein
when a first memory information is written into the memory cell, the drive circuit flows a first write current to the first signal line, a second write current directed opposite to the first write current to the second signal line, and a third write current to a third signal line to apply to a first magnetoresistance effect element a synthetic magnetic field of a magnetic field generated by the first write current and a magnetic field generated by the third write current and apply to a second magnetoresistance effect element a synthetic magnetic field of a magnetic field generated by the second write current and a magnetic field generated by the third write current, and
when a second memory information is written in the memory cell, the drive circuit flows a fourth write current directed opposite to the first write current to the first signal line, a fifth write current of the same direction as the first write current to the second signal line, a sixth write current of the same direction as the third write current to the third signal line to apply the first magnetoresistance effect element a synthetic magnetic field of a magnetic field generated by the fourth write current and a magnetic field generated by the sixth write current and apply to the second magnetoresistance effect element a synthetic magnetic field of a magnetic field generated by the fifth write current and a magnetic field generated by the sixth write current.

### Claim 13 (depends on 9)

The magnetic memory device according to claim 9,
which includes: a plurality of said memory cells, and a plurality of said first signal lines and a plurality of said second signal lines which are respectively connected to said respective plural memory cells, and
which further comprises: a drive circuit for writing memory information into the plurality of said memory cells, wherein
for said respective plurality of memory cells, the drive circuit sets directions of said write currents to be flowed to the first signal lines and the second signal lines discretely corresponding to information-to-be-memorized to be written and flows said write currents to thereby write simultaneously into said respective plurality of memory cells.

### Claim 14 (depends on 9)

The magnetic memory device according to claim 9,
which includes: a plurality of said memory cells, and a plurality of said first signal lines and a plurality of said second signal lines which are respectively connected to said respective plural memory cells, and
which further comprises:
a first current source disposed on a side of one ends of the first signal line and the second signal line;
a second current source disposed on a side of the other ends of the first signal lines and the second signal lines; and
a drive circuit for driving the first current source and the second current source for writing information into the plurality of said memory cells,
wherein the drive circuit drives the first current source and the second current source so as to supply said first write current or the fifth write current from the first current source to, and to supply said second write current or the fourth write current from the second current source.

### Claim 15 (depends on 9)

The magnetic memory device according to claim 9, further comprising:
a current source disposed on a side of one ends of the first signal line and the second signal line;
a switching element disposed on a side of the other ends of the first signal line and the second signal line, for electrically connecting or disconnecting the first signal line and the second signal line; and
a drive circuit for driving the current source for writing information into the memory cell,
wherein when a memory information is written, the drive current drives the current source and the switching element so as to electrically connect the first signal line and the second signal line to each other by the switching element to form a current path of the first signal line and the second signal line connected to each other, and to supply the write current from the current source to the current path of the first signal line and the second signal line.

### Claim 16 (depends on 9)

The magnetic memory device according to claim 9,
which includes: a plurality of said memory cells, and a plurality of said first signal lines and a plurality of said second signal lines which are respectively connected to said respective plural memory cells, and
which further comprises:
a current source disposed on a side of one ends of the first signal line and the second signal line;
a switching element disposed on a side of the other ends of the first signal line and the second signal line, for electrically connecting or disconnecting the first signal line and the second signal line; and
a drive circuit for driving the current source for writing information into the memory cell,
wherein when a memory information is written, the drive current drives the current source and the switching element so as to electrically connect the first signal line and the second signal line to each other by the switching element to form a current path of the first signal line and the second signal line connected to each other, and to supply the write current from the current source to the current path of the first signal line and the second signal line.