# US 2014/0191182 A1 · Memory Cells

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- Number: US 2014/0191182 A1
- Document ID: US20140191182A1
- Status: Published application
- Kind: A1
- Application number: 13/738,201
- Filed: 2013-01-10
- Published: 2014-07-10
- Earliest claimed: 2013-01-10
- Assignees: Micron Technology, Inc.
- Applicants: Micron Technology, Inc.
- Inventors: Shuichiro Yasuda; Noel Rocklein; Scott E. Sills; D.V. Nirmal Ramaswamy; Qian Tao
- Web page: https://patentgrep.com/patent/US20140191182A1

## CPC

- H10N 70/023: {by chemical vapor deposition, e.g. MOCVD, ALD}
- H10N 70/20: Multistable switching devices, e.g. memristors
- H10N 70/245: {the species being metal cations, e.g. programmable metallization cells}
- H10N 70/826: {adapted for essentially vertical current flow, e.g. sandwich or pillar type devices}
- H10N 70/841: {Electrodes}
- H10N 70/8416: {adapted for supplying ionic species}
- H10N 70/883: {Oxides or nitrides}
- H10N 70/8833: {Binary metal oxides, e.g. TaOx}
- H10N 70/8836: {Complex metal oxides, e.g. perovskites, spinels}
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

Some embodiments include a method of forming a memory cell. A first portion of a switching region is formed over a first electrode. A second portion of the switching region is formed over the first portion using atomic layer deposition. The second portion is a different composition than the first portion. An ion source region is formed over the switching region. A second electrode is formed over the ion source region. Some embodiments include a memory cell having a switching region between a pair of electrodes. The switching region is configured to be reversibly transitioned between a low resistive state and a high resistive state. The switching region includes two or more discrete portions, with one of the portions not having a non-oxygen component in common with any composition directly against it in the high resistive state.

## Claims

### Claim at position 1

1-28. (canceled)

### Claim 29

A memory cell, comprising:
a switching region located between a pair of electrodes and comprising a first discrete portion and a second discrete portion, with the first discrete portion having a thickness within a range of from greater than 0 angstroms to less than or equal to about 20 angstroms and not having a non-oxygen component in common with any composition directly against the first discrete portion in a high resistive state of the memory cell, at least one of the first and second discrete portions being formed by atomic layer deposition which provides enhanced switchability and retention of the cell.

### Claim 30 (depends on 29)

The memory cell of claim 29 wherein one of first and second discrete portions is thicker than the other.

### Claim 31 (depends on 29)

The memory cell of claim 29 wherein one of the first and second discrete portions of the switching region comprises one or more of aluminum, hafnium, silicon, titanium and zirconium.

### Claim 32 (depends on 29)

The memory cell of claim 29 wherein one of the first and second discrete portions of the switching region has a thickness of less than one monolayer.

### Claim 33 (depends on 29)

The memory cell of claim 29 wherein:
the first discrete portion consists of oxygen in combination with one or more transition metals; and
the second discrete portion consists of oxygen in combination with one or more non-transition elements; wherein said non-transition elements are selected from the group consisting of metals, semi-metals, alkaline earth elements, and mixtures thereof.

### Claim 34 (depends on 29)

The memory cell of claim 29 wherein:
the first discrete portion consists of oxygen in combination with one or more non-transition elements; wherein said non-transition elements are selected from the group consisting of metals, semi-metals, alkaline earth elements, and mixtures thereof; and
the second discrete portion consists of oxygen in combination with one or more transition metals.