# US 7,411,262 B2 · Self-aligned, low-resistance, efficient memory array

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- Number: US 7,411,262 B2
- Document ID: US7411262B2
- Status: Granted
- Kind: B2
- Application number: 11/212,646
- Filed: 2005-08-29
- Published: 2006-01-05
- Granted: 2008-08-12
- Earliest claimed: 2003-04-09
- Assignees: Micron Technology, Inc.
- Inventors: James G. Deak
- Web page: https://patentgrep.com/patent/US7411262B2

## CPC

- G11C 11/16: using elements in which the storage effect is based on magnetic spin effect
- H10B 61/00: Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
- H10N 50/01: Manufacture or treatment
- H10N 50/10: Magnetoresistive devices
- Y10T 29/49021: Magnetic recording reproducing transducer [e.g., tape head, core, etc.]
- Y10T 29/49044: Plural magnetic deposition layers
- G11C: STATIC STORES (semiconductor memory devices H10B)
- H10B: ELECTRONIC MEMORY DEVICES
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present invention seeks to reduce the amount of current required for a write operation by using a process for forming the read conductor within a recessed write conductor, the write conductor itself formed within a trench of an insulating layer. The present invention protects the MTJ from the voltages created by the write conductor by isolating the write conductor and enabling the reduction of current necessary to write a bit of information.

## Claims

### Claim 1

A memory array structure, comprising:
a plurality of memory cell structures, each of said memory cell structures comprising:
a trench in a first insulating layer defining first and second levels, said and second levels being connected by at least a sidewall region;
a ferromagnetic cladding layer formed within said trench and over said second level and said sidewall region of said first insulating layer;
a first conductive layer formed within said trench and over a second level and a sidewall region of said ferromagnetic cladding layer;
a second insulating layer formed within said trench and over a second level and a sidewall region of said first conductive layer;
a second conductive layer formed within said trench; and
a magnetic tunnel junction element formed over said second conductive layer.

### Claim 2 (depends on 1)

The memory array structure of claim 1, further comprising said first insulating layer formed over a semiconductor substrate.

### Claim 3 (depends on 1)

The memory array structure of claim 1, wherein said first conductive layer is a write conductor, and said second conductive layer is a read conductor.

### Claim 4 (depends on 1)

The memory array structure of claim 1, wherein said first and second conductive layers are formed of a material selected from the group consisting of tungsten-nitride, tungsten, platinum, gold, silver, aluminum, and copper.

### Claim 5 (depends on 1)

The memory array structure of claim 1, wherein a topmost surface of said second conductive layer is planar to a topmost surface of said first conductive layer.

### Claim 6 (depends on 1)

The memory array structure of claim 1, wherein said topmost surface of said second conductive layer, and said topmost surface of said first conductive layer are planar to a topmost surface of said first insulating layer.

### Claim 7 (depends on 1)

The memory array structure of claim 1, further comprising a liner formed between said first insulating layer and said ferromagnetic cladding layer.

### Claim 8 (depends on 1)

The memory array structure of claim 1, further comprising a barrier layer formed between said ferromagnetic cladding layer and said first conductive layer.

### Claim 9 (depends on 1)

The memory array structure of claim 1, further comprising a liner formed between said ferromagnetic cladding layer and said first conductive layer.

### Claim 10 (depends on 1)

The memory array structure of claim 1, wherein said magnetic tunnel junction element comprises:
a pinned magnetic layer;
a tunnel barrier layer; and
a free magnetic layer.

### Claim 11

A memory device comprising a plurality of magnetoresistive random access memory cell structures arranged in an array, each of said magnetoresistive random access memory cell structures comprising:
a trench in a first insulating layer defining first and second levels, said and second levels being connected by at least a sidewall region;
a ferromagnetic cladding layer formed within said trench and over said second level and said sidewall region of said first insulating layer;
a first conductive layer formed within said trench and over a second level and a sidewall region of said ferromagnetic cladding layer;
a second insulating layer formed within said trench and over a second level and a sidewall region of said first conductive layer;
a second conductive layer formed within said trench; and
a magnetic tunnel junction element formed over said second conductive layer.

### Claim 12

A memory cell array comprising:
a plurality of magnetoresistive random access memory cell structures, each of said magnetoresistive random access memory cell structures comprising:
a trench in a first insulating layer defining first and second levels, said and second levels being connected by at least a sidewall region;
a ferromagnetic cladding layer formed within said trench and over said second level and said sidewall region of said first insulating layer;
a first conductive layer formed within said trench and over a second level and a sidewall region of said ferromagnetic cladding layer;
a second insulating layer formed within said trench and over a second level and a sidewall region of said first conductive layer;
a second conductive layer formed within said trench; and
a magnetic tunnel junction element formed over said second conductive layer.