# US 8,772,123 B2 · Band gap improvement in DRAM capacitors

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- Number: US 8,772,123 B2
- Document ID: US8772123B2
- Status: Granted
- Kind: B2
- Application number: 13/237,065
- Filed: 2011-09-20
- Published: 2013-03-21
- Granted: 2014-07-08
- Earliest claimed: 2010-11-09
- Assignees: Intermolecular, Inc.; Elpida Memory, Inc.
- Applicants: Hanhong Chen; Sandra G. Malhotra; Wim Deweerd; Hiroyuki Ode
- Inventors: Hanhong Chen; Sandra G. Malhotra; Wim Deweerd; Hiroyuki Ode
- Web page: https://patentgrep.com/patent/US8772123B2

## CPC

- H10D 1/68: Capacitors having no potential barriers
- H10B 12/03: {Making the capacitor or connections thereto}
- H10D 1/692: {Electrodes}
- H10P 14/6339: {deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD}
- H10P 14/69391: {the material containing aluminium, e.g. Al2O3}
- H10P 14/69392: {the material containing hafnium, e.g. HfO2}
- H10P 14/69394: {the material containing titanium, e.g. TiO2}
- H10P 14/69395: {the material containing zirconium, e.g. ZrO2}
- H10P 14/69397: {the material containing two or more metal elements}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10B: ELECTRONIC MEMORY DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A method for forming a DRAM MIM capacitor stack having low leakage current and low EOT involves the use of an compound high k dielectric material. The dielectric material further comprises a dopant. One component of the compound high k dielectric material is present in a concentration between about 30 atomic % and about 80 atomic % and more preferably between about 40 atomic % and about 60 atomic %. In some embodiments, the compound high k dielectric material comprises an alloy of TiO2 and ZrO2 and further comprises a dopant of Al2O3. In some embodiments, the compound high k dielectric material comprises an admixture of TiO2 and HfO2 and further comprises a dopant of Al2O3.

## Claims

### Claim 1

A method for forming a capacitor stack comprising:
forming a first electrode layer on a substrate,
the first electrode layer comprising MoO2;
forming a compound high k dielectric material on the first electrode layer,
wherein the compound high k dielectric material is formed by admixing two or more high k dielectric material components,
wherein one of the two or more high k dielectric material components comprises TiO2,
wherein at least 30% of TiO2 is present in a rutile phase, and
wherein a concentration of one of the components of the compound high k dielectric material is in the range between about 30 atomic % and about 80 atomic %; and
forming a second electrode on the compound high k dielectric material.

### Claim 2 (depends on 1)

The method of claim 1 wherein the concentration of the one of the two or more high k dielectric material components of the compound high k material is in the range between about 40 atomic % and about 60 atomic %.

### Claim 3 (depends on 1)

The method of claim 1 wherein another one of the two or more high k dielectric material components is selected from the group consisting of SiO2, a bilayer of SiO2 and SiXNY, SiON, Al2O3, HfO2, HfSiOX, ZrO2, Ta2O5, Nb2O5, SrTiO3 (STO), BaSrTiOx (BST), and PbZrTiOX (PZT).

### Claim 4 (depends on 3)

The method of claim 3 wherein another one of the two or more high k dielectric material components comprises ZrO2.

### Claim 5 (depends on 4)

The method of claim 4 wherein the concentration of the ZrO2 is in the range between about 30 atomic % and about 80 atomic %.

### Claim 6 (depends on 5)

The method of claim 5 wherein the concentration of the ZrO2 is in the range between about 40 atomic % and about 60 atomic %.

### Claim 7 (depends on 4)

The method of claim 4 wherein the compound high k dielectric material comprises a dopant.

### Claim 8 (depends on 7)

The method of claim 7 wherein the dopant is one of Al, Ge, Hf, Sn, Sr, Y, Si, La, Er, Ga, Gd, Mg, Co, or combinations thereof.

### Claim 9 (depends on 7)

The method of claim 7 wherein the dopant comprises Al2O3 and wherein the Al is present in an amount between about 5 atomic % and about 15 atomic %.

### Claim 10 (depends on 3)

The method of claim 3 wherein the other one of the two or more high k dielectric material components comprises HfO2.

### Claim 11 (depends on 10)

The method of claim 10 wherein the concentration of the HfO2 is in the range between about 30 atomic % and about 80 atomic %.

### Claim 12 (depends on 11)

The method of claim 11 wherein the concentration of the HfO2 is in the range between about 40 atomic % and about 60 atomic %.

### Claim 13 (depends on 10)

The method of claim 10 wherein the compound high k dielectric material comprises a dopant.

### Claim 14 (depends on 13)

The method of claim 13 wherein the dopant is one of Al, Zr, Ge, Sn, Sr, Y, Si, La, Er, Ga, Gd, Mg, Co, or combinations thereof.

### Claim 15 (depends on 13)

The method of claim 13, wherein the dopant comprises Al2O3 and wherein the Al is present in an amount between about 5 atomic % and about 15 atomic %.

### Claim 16 (depends on 1)

The method of claim 1, wherein the second electrode is TiN.

### Claim 17 (depends on 16)

The method of claim 16 wherein the compound high k dielectric material further comprises a dopant of Al2O3.

### Claim 18 (depends on 10)

The method of claim 10 wherein the second electrode is TiN.

### Claim 19 (depends on 18)

The method of claim 18 wherein the compound high k dielectric material further comprises a dopant of Al2O3.