# US 7,071,007 B2 · Method of forming a low voltage drive ferroelectric capacitor

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- Number: US 7,071,007 B2
- Document ID: US7071007B2
- Status: Granted
- Kind: B2
- Application number: 10/313,776
- Filed: 2002-12-06
- Published: 2004-06-10
- Granted: 2006-07-04
- Earliest claimed: 2002-12-06
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Yuan-Chieh Tseng; Chao-Hsiung Wang; Tai-Bor Wu
- Web page: https://patentgrep.com/patent/US7071007B2

## CPC

- H10D 1/682: {having dielectrics comprising perovskite structures}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A method of forming a low-voltage drive thin film ferroelectric capacitor includes the steps of depositing a ferroelectric and platinum thin film dielectric layer over a bottom electrode, annealing the dielectric layer, wherein a nanocomposite layer is formed including nanoparticles of platinum and forming a top electrode over the dielectric layer. An integrated circuit is also provided including a ferroelectric capacitor. The capacitor includes a bottom electrode formed over a substrate and a ferroelectric and platinum thin film nanocomposite dielectric layer formed over the bottom electrode, wherein the nanocomposite layer includes nanoparticles of platinum. A top electrode is formed over the dielectric layer.

## Claims

### Claim 1

A method of forming a low-voltage drive thin film ferroelectric capacitor, comprising the steps of:
depositing a thin film dielectric layer over a bottom electrode, said thin film dielectric layer comprising a ferroelectric material with platinum dispersed therein;
annealing said dielectric layer, wherein a nanocomposite layer is formed including nanoparticles of platinum; and
forming a top electrode over said dielectric layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein at least said bottom electrode includes a LaNiO3 layer.

### Claim 3 (depends on 1)

The method of claim 1, wherein said dielectric layer comprises a PZT-platinum thin film.

### Claim 4 (depends on 3)

The method of claim 3, wherein said PZT-platinum thin film is less than approximately 10% platinum.

### Claim 5 (depends on 3)

The method of claim 3, wherein said PZT-platinuni thin film is deposited to a thickness of less than approximately 2000 Å.

### Claim 6 (depends on 3)

The method of claim 3, wherein said annealing step is for approximately 3 to 10 minutes in an oxidization ambient at a temperature between approximately 250–750° C.

### Claim 7 (depends on 3)

The method of claim 3, wherein said depositing step includes the step of sputter depositing said PZT-Pt thin film.

### Claim 8 (depends on 7)

The method of claim 7, wherein said PZT-platinum thin film is formed by co-sputtering using a PZT target and a platinum target.

### Claim 9 (depends on 3)

The method of claim 3, wherein said depositing step includes the step of forming said PZT-platinum thin film by chemical vapor deposition.

### Claim 10 (depends on 1)

The method of claim 1, wherein substantially all of said platinum nanoparticles have dimensions less than about 30 nm.

### Claim 11 (depends on 1)

The method of claim 1, wherein said dielectric layer comprises a PZT-platinum thin film and said thin film is between about 2.5–8.5% platinum.

### Claim 12 (depends on 1)

The method of claim 1, wherein said annealing step comprises a rapid thermal anneal.

### Claim 13 (depends on 1)

The method of claim 1, wherein said annealing process comprises a pulsed laser annealing.

### Claim 14 (depends on 13)

The method of claim 13, wherein said pulsed laser annealing is for less than or about 30 seconds at a temperature of greater than or about 700° C.

### Claim 15

A method of forming a low-voltage drive thin film ferroelectric capacitor, comprising the steps of:
forming a bottom electrode having a LaNiO3 layer over a substrate;
depositing a dielectric layer including a PZT-Pt thin film over said bottom electrode;
performing a rapid thermal anneal on said substrate, wherein a PZT-Pt nanocomposite layer is formed including nanoparticles of platinum fixed in a PZT matrix; and
forming a top electrode over said dielectric layer.

### Claim 16 (depends on 15)

The method of claim 15, wherein PZT-Pt thin film is less than approximately 10% platinum.

### Claim 17 (depends on 15)

The method of claim 15, wherein said annealing step is approximately 180 seconds or less in an oxidation ambient at a temperature between about 450–850° C.

### Claim 18 (depends on 15)

The method of claim 15, wherein said PZT-Pt thin film is formed by co-sputtering process using a PZT target and a platinum target.

### Claim 19 (depends on 15)

The method of claim 15, wherein substantially all of said platinum nanoparticles have dimensions less than about 30 nm.

### Claim 20

A method of forming a low-voltage drive thin film ferroelectric capacitor, comprising the steps of:
co-sputtering using at least a first and second targets a thin film dielectric layer over a bottom electrode, said thin film dielectric layer comprising a ferroelectric material and platinum;
annealing said dielectric layer, wherein a nanocomposite layer is formed including nanoparticles of platinum fixed in said ferroelectric material; and
forming a top electrode over said dielectric layer.

### Claim 21 (depends on 20)

The method of claim 20, wherein at least said bottom electrode includes a LaNiO3 layer.

### Claim 22 (depends on 20)

The method of claim 20, wherein said ferroelectric material comprises PZT.

### Claim 23 (depends on 20)

The method of claim 20, wherein said thin film dielectric layer comprises less than approximately 10% platinum.

### Claim 24 (depends on 20)

The method of claim 20, wherein said thin film dielectric layer is deposited to a thickness of less than approximately 2000 Å.

### Claim 25 (depends on 20)

The method of claim 20, wherein said thin film dielectric layer is deposited to a thickness of less than approximately 1500 Å.

### Claim 26 (depends on 20)

The method of claim 20, wherein said annealing step is for approximately 3 to 10 minutes in an oxidization ambient at a temperature between approximately 250–750° C.

### Claim 27 (depends on 20)

The method of claim 20, wherein substantially all of said platinum nanopartioles have dimensions less than about 70 nm.

### Claim 28 (depends on 20)

The method of claim 20, wherein substantially all of said platinum nanoparticles have dimensions less than about 30 nm.

### Claim 29 (depends on 28)

The method of claim 28, wherein said ferroelectric material comprises PZT and said thin film dielectric layer comprises between about 2.5–8.5% platinum.

### Claim 30

A method of forming a low-voltage drive thin film ferroelectric capacitor, comprising the steps of:
depositing via chemical vapor deposition a thin film dielectric layer over a bottom electrode, said thin film dielectric layer comprising a ferroelectric material and platinum;
annealing said dielectric layer, wherein a nanocomposite layer is formed including nanoparticles of platinum fixed in said ferroelectric material; and
forming a top electrode over said dielectric layer.

### Claim 31 (depends on 30)

The method of claim 30, wherein at least said bottom electrode includes a LaNiO3 layer.

### Claim 32 (depends on 30)

The method of claim 30, wherein said ferroelectric material comprises PZT.

### Claim 33 (depends on 30)

The method of claim 30, wherein said thin film dielectric layer comprises less than approximately 10% platinum.

### Claim 34 (depends on 30)

The method of claim 30, wherein said thin film dielectric layer is deposited to a thickness of less than approximately 2000 Å.

### Claim 35 (depends on 30)

The method of claim 30, wherein said thin film dielectric layer is deposited to a thickness of less than approximately 1500 Å.

### Claim 36 (depends on 30)

The method of claim 30, wherein said annealing step is for approximately 3 to 10 minutes in an oxidization ambient at a temperature between approximately 250–750° C.

### Claim 37 (depends on 30)

The method of claim 30, wherein substantially all of said platinum nanoparticles have dimensions less than about 70 nm.

### Claim 38 (depends on 30)

The method of claim 30, wherein substantially all of said platinum nanoparticles have dimensions less than about 30 nm.

### Claim 39 (depends on 38)

The method of claim 38, wherein said ferroelectric material comprises PZT and said thin film dielectric layer comprises between about 2.5–8.5% platinum.

### Claim 40

A method of forming a low-voltage drive thin film ferroelectric capacitor, comprising the steps of:
forming a bottom electrode comprising a LaNiO3 layer over a substrate;
depositing a dielectric layer including a PZT-Pt thin film over said bottom-electrode, said dielectric layer having a thickness of less than about 2000 Å, said PZT-Pt thin film comprising between about 2.5–8.5% Pt;
performing a rapid thermal anneal on said substrate, wherein a PZT-Pt nanocomposite layer is formed including nanoparticles of platinum fixed in a PZT matrix, wherein substantially all of said platinum nanoparticles have dimensions less than about 30 nm; and
forming a top electrode over said dielectric layer.

### Claim 41 (depends on 40)

The method of claim 40, wherein said rapid thermal anneal step is performed for between about 30–180 seconds at a temperature between about 450–850° C.