# US 7,745,233 B2 · Ferroelectric capacitor and ferroelectric memory with Ir-Ru alloy electrode and method of manufacturing the same

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- Number: US 7,745,233 B2
- Document ID: US7745233B2
- Status: Granted
- Kind: B2
- Application number: 12/289,494
- Filed: 2008-10-29
- Published: 2009-04-16
- Granted: 2010-06-29
- Earliest claimed: 2004-07-28
- Assignees: Samsung Electronics Co., Ltd.
- Inventors: Sang-min Shin; Suk-pil Kim; Young-soo Park; Jung-hyun Lee; June-mo Koo
- Web page: https://patentgrep.com/patent/US7745233B2

## CPC

- H10B 53/00: Ferroelectric RAM [FeRAM] devices comprising ferroelectric memory capacitors
- H10D 1/682: {having dielectrics comprising perovskite structures}
- H10D 1/694: {comprising noble metals or noble metal oxides}
- H10B: ELECTRONIC MEMORY DEVICES
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A ferroelectric capacitor comprises a first electrode comprising an alloy of Ir and Ru, a ferroelectric layer disposed on the first electrode, and a second electrode disposed on the ferroelectric layer. A ferroelectric memory comprises a substrate and a plurality of memory cells arranged on the substrate. Each memory cell comprises a first electrode comprising an alloy of Ir and Ru, a ferroelectric layer disposed on the first electrode, and a second electrode disposed on the ferroelectric layer.

## Claims

### Claim 1

A method of fabricating a ferroelectric capacitor, comprising:
forming a first electrode an of Ir and Ru, wherein the alloy is a multi-phase alloy with a first phase containing Ir and Ru and a second phase containing Ir and Ru, the alloy having a mixture of grains of an alpha (α) phase of an Ir-rich solid solution and a beta (β) phase of a Ru-rich solid solution;
forming a ferroelectric layer on the first electrode; and
forming a second electrode on the ferroelectric layer.

### Claim 2

A method of fabricating a ferroelectric memory, comprising:
forming a plurality of memory cells on a substrate, wherein each memory cell includes
a first electrode comprising an alloy of Ir and Ru, wherein the alloy is a multi-phase alloy with a first phase containing Ir and Ru and a second phase containing Ir and Ru, the alloy having a mixture of grains of an alpha (α) phase of an Ir-rich solid solution and a beta (β) phase of a Ru-rich solid solution,
a ferroelectric layer disposed on the first electrode, and
a second electrode disposed on the ferroelectric layer.

### Claim 3 (depends on 1)

The method of claim 1, wherein the alloy has an average composition of RuxIr1-x, x being in the range of 30 to 70 atomic percent.

### Claim 4 (depends on 1)

The method of claim 1, wherein the alloy has an average composition of RuxIr1-x, x being in the range of 35 to 55 atomic percent.

### Claim 5 (depends on 1)

The method of claim 1, wherein the alloy has an average composition of RuxIr1-x, x being in the range of 35 to 45 atomic percent.

### Claim 6 (depends on 1)

The method of claim 1, wherein the alloy has an average composition of about Ru40Ir60.

### Claim 7 (depends on 1)

The method of claim 1, wherein the ferroelectric layer comprises one of lead-zirconate-titanate, strontium-bismuth-tantalate, bismuth-lanthanum-titanate and barium-strontium-titanate.

### Claim 8 (depends on 1)

The method of claim 1, wherein forming the first electrode comprises depositing the first electrode by one of sputtering, chemical vapor deposition and atomic layer deposition.

### Claim 9 (depends on 2)

The method of claim 2, wherein the alloy has an average composition of RuxIr1-x, x being in the range of 30 to 70 atomic percent.

### Claim 10 (depends on 2)

The method of claim 2, wherein the alloy has an average composition of RuxIr1-x, x being in the range of 35 to 55 atomic percent.

### Claim 11 (depends on 2)

The method of claim 2, wherein the alloy has an average composition of RuxIr1-x, x being in the range of 35 to 45 atomic percent.

### Claim 12 (depends on 2)

The method of claim 2, wherein the alloy has an average composition of about Ru40Ir60.

### Claim 13 (depends on 2)

The method of claim 2, wherein the ferroelectric layer comprises one of lead-zirconate-titanate, strontium-bismuth-tantalate, bismuth-lanthanum-titanate and barium-strontium-titanate.

### Claim 14 (depends on 2)

The method of claim 2, comprising depositing the first electrode by one of sputtering, chemical vapor deposition and atomic layer deposition.

### Claim 15 (depends on 2)

The method of claim 2, wherein forming the first electrode comprises depositing the first electrode by one of sputtering, chemical vapor deposition and atomic layer deposition.

### Claim 16 (depends on 2)

The method of claim 2, comprising forming a barrier layer at a surface of the second electrode being arranged between the barrier layer and the ferroelectric layer.