# US 10,312,442 B2 · Non-volatile memory devices, RRAM devices and methods for fabricating RRAM devices with magnesium oxide insulator layers

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- Number: US 10,312,442 B2
- Document ID: US10312442B2
- Status: Granted
- Kind: B2
- Application number: 15/711,370
- Filed: 2017-09-21
- Published: 2019-03-21
- Granted: 2019-06-04
- Earliest claimed: 2017-09-21
- Assignees: Globalfoundries Singapore Pte. Ltd.
- Applicants: Globalfoundries Singapore Pte. Ltd.
- Inventors: Danny Pak-Chum Shum; Desmond Jia Jun Loy; Wen Siang Lew
- Web page: https://patentgrep.com/patent/US10312442B2

## CPC

- H10N 70/8833: {Binary metal oxides, e.g. TaOx}
- H10B 63/30: {comprising selection components having three or more electrodes, e.g. transistors}
- H10N 70/026: {by physical vapor deposition, e.g. sputtering}
- 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 70/8416: {adapted for supplying ionic species}
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

Non-volatile memory (NVM) devices, resistive random access memory (RRAM) devices and methods for fabricating such devices are provided. In an exemplary embodiment, a non-volatile memory (NVM) device includes a first electrode and a second electrode positioned above the first electrode. Further, the NVM device includes a variable resistance material layer positioned between the first electrode and the second electrode. The variable resistance material layer contains magnesium oxide.

## Claims

### Claim 1

A non-volatile memory (NVM) device comprising:
a substrate;
a first electrode;
a seed layer positioned between the substrate and the first electrode;
a second electrode positioned above the first electrode; and
a single variable resistance material layer positioned between the first electrode and the second electrode and having a first surface in direct contact with the first electrode and a second surface in direct contact with the second electrode, wherein the variable resistance material layer contains magnesium oxide.

### Claim 2 (depends on 1)

The device of claim 1 wherein the first electrode is comprised of at least one of ruthenium (Ru), platinum (Pt), indium (In), molybdenum (Mo), and tungsten (W).

### Claim 3 (depends on 1)

The device of claim 1 wherein the second electrode is comprised of at least one of tantalum (Ta), hafnium (Hf), titanium (Ti), titanium nitride (TiN), cobalt (Co), gold (Au), indium tin oxide (ITO), copper (Cu), and silver (Ag).

### Claim 4 (depends on 1)

The device of claim 1 wherein the seed layer is comprised of tantalum, platinum, gold, or copper.

### Claim 5 (depends on 1)

The device of claim 1 further comprising a capping layer over the second electrode.

### Claim 6 (depends on 5)

The device of claim 5 wherein the capping layer is comprised of gold (Au).

### Claim 7 (depends on 5)

The device of claim 5 wherein:
the seed layer has a thickness of from about 2 nm to about 10 nm;
the first electrode has a thickness of from about 5 nm to about 20 nm;
the variable resistance material layer has a thickness of from about 5 nm to about 20 nm;
the second electrode has a thickness of from about 20 nm to about 40 nm; and
the capping layer has a thickness of from about 5 nm to about 20 nm.

### Claim 8 (depends on 1)

The device of claim 1 wherein:
the first electrode has a thickness of from about 5 nm to about 20 nm;
the variable resistance material layer has a thickness of from about 5 nm to about 20 nm; and
the second electrode has a thickness of from about 20 nm to about 40 nm.

### Claim 9 (depends on 1)

The device of claim 1 wherein:
the first electrode is comprised of ruthenium (Ru);
the second electrode is comprised of tantalum (Ta); and
the device uses valence change mechanism (VCM) as a switching mechanism.

### Claim 10 (depends on 1)

The device of claim 1 wherein:
the first electrode is comprised of ruthenium (Ru);
the second electrode is comprised of copper (Cu); and
the device uses electrochemical metallization memory (ECM) as a switching mechanism.

### Claim 11 (depends on 1)

The device of claim 1 wherein the device uses a Schottky emission-based switching mechanism.

### Claim 12 (depends on 1)

The device of claim 1 wherein the device uses electrochemical metallization memory (ECM) as a switching mechanism.

### Claim 13

A resistive random access memory (RRAM) device comprising:
a substrate;
a magnesium oxide (MgO) based metal-insulator-metal (MIM) structure overlying the substrate and comprising a first electrode over the substrate, an insulator over the first electrode, and a second electrode over the insulator; and
a seed layer between the substrate and the first electrode.

### Claim 14 (depends on 13)

The device of claim 13 wherein:
the first electrode is comprised of at least one of ruthenium (Ru), platinum (Pt), indium (In), molybdenum (Mo), and tungsten (W);
the second electrode is comprised of at least one of tantalum (Ta), hafnium (Hf), titanium (Ti), titanium nitride (TiN), cobalt (Co), gold (Au), indium tin oxide (ITO), copper (Cu), and silver (Ag); and
the insulator layer is a magnesium oxide (MgO) insulator layer.

### Claim 15 (depends on 14)

The device of claim 14 further comprising a capping layer over the second electrode.

### Claim 16 (depends on 13)

The device of claim 13 wherein the device uses valence change mechanism (VCM) as a switching mechanism.

### Claim 17

A method for fabricating a resistive random access memory (RRAM) device comprising:
forming a first electrode over a substrate;
forming a magnesium oxide (MgO)-containing insulator layer over the first electrode; and
forming a second electrode over the MgO-containing insulator layer;
wherein forming the first electrode over the substrate comprises patterning a first mask over the substrate, depositing a first electrode material over the substrate, and removing the first mask and overlying layers from the substrate; and
wherein forming the magnesium oxide (MgO)-containing insulator layer over the first electrode and forming the second electrode over the MgO-containing insulator layer comprises patterning a second mask over the first electrode and the substrate, depositing MgO-containing material over the substrate and the first electrode, depositing a top electrode material over the MgO-containing material, and removing the second mask and overlying layers from the substrate.

### Claim 18 (depends on 17)

The method of claim 17 wherein:
depositing the first electrode material over the substrate comprises sputtering the first electrode material over the substrate; and
depositing the MgO-containing material over the substrate and the first electrode comprises sputtering the MgO-containing material over the substrate and the first electrode; and
depositing the top electrode material over the MgO-containing material comprises sputtering the top electrode material over the MgO-containing material.