US6010744A
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Method for nucleation controlled chemical vapor deposition of metal oxide ferroelectric thin films
Assignee: Infineon Technologies AG
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Filing: 1997-12-23
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Granted: 2000-01-04
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Expires: 2017-12-23
Abstract
Abstract A method is described for the nucleation controlled deposition of ferroelectric thin films by chemical vapor deposition in a novel processing sequence wherein a higher density of bismuth nucleation sites is achieved either by the use of a substrate member which has been treated in a manner to yield a controllably and reproducible rough surface on which SBT films with excellent properties may be produced or by using a chemically modified substrate surface upon which surface chemical properties are modified. Typical techniques for achieving surface roughening include reactive ion etching, inert ion milling and chemical mechanical polishing, each of which may be used to delineate patterned bottom electrodes. The chemical properties of the substrate may be modified by alloy deposition, deposition of seed layers which are then partially or completely in-diffused ion implantation with or without heat treatment and changing the chemistry of the surface by a pre-exposure to chemical agents prior to deposition. The resultant oxide ferroelectric thin films are suitable for use in capacitors, memory devices and the like.
Inventors
- 👤 Peter Van Buskirk
- 👤 Jeff Roeder
- 👤 Frank Hintermaier
- 👤 Bryan Hendrix
- 👤 Thomas H. Baum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:56
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/02; C23C16/0272; H; H10; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6326; H10P14/6328; H10P14/6334; C23C16/04; C23C16/22; C23C16/30; C23C16/40; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/682; H10D1/684; H10P14/65; H10P14/6502; H10P14/69; H10P14/692; H10P14/6938; H10P14/69398; Y; Y10; Y10S; Y10S977/00; Y10S977/84; Y10S977/89; Y10S977/891
Claims Analysis
Total Claims: 49
Claim 1
Independent Claim
135 words
A method for the nucleation controlled deposition of thin films suitable for use as the dielectric of a capacitor on a substrate member by metal-organic chemical vapor deposition which comprises the steps of: (a) placing the substrate member in a chemical vapor deposition apparatus, the substrate having deposited upon a portion thereof a film of an electrically conductive material; (b) heating the substrate to an elevated temperature in the range of from about 300° C. to 800° C. within the apparatus; (c) introducing vaporized metal-organic precursors carried by an inert gas into the apparatus, and thermally decomposing the precursors to substantially simultaneously yield a first thin film of a homogenous composition upon the electrically conductive material, and a second thin film of a composition different from the first thin film upon the exposed substrate surface.
Claim 2
Independent Claim
135 words
A method for the nucleation controlled deposition of thin films suitable for use as the dielectric of a capacitor on a substrate member by metal-organic chemical vapor deposition which comprises the steps of: (a) placing the substrate member in a chemical vapor deposition apparatus, the substrate having deposited upon a portion thereof a film of an electrically conductive material; (b) heating the substrate to an elevated temperature in the range of from about 300° C. to 800° C. within the apparatus; (c) introducing vaporized metal-organic precursors carried by an inert gas into the apparatus, and thermally decomposing the precursors to substantially simultaneously yield a first thin film of a homogenous composition upon the electrically conductive material, and a second thin film of a composition different from the first thin film upon the exposed substrate surface.
Claim 3
Dependent Claim
16 words
The method in accordance with claim 1 wherein the first thin film is a dielectric material.
Claim 4
Dependent Claim
26 words
The method in accordance with claim 2 wherein the dielectric material is a ferroelectric material or a material capable of being transformed into a ferroelectric material.
Claim 5
Dependent Claim
19 words
The method in accordance with claim 3 wherein the ferroelectric material is a ceramic material with a perovskite structure.
Claim 6
Dependent Claim
15 words
The method in accordance with claim 4 wherein the ferroelectric material has an Aurivillius structure.
Claim 7
Dependent Claim
22 words
The method in accordance with claim 5 wherein the ferroelectric material is SrBi 2 Ta 2 O 9 or a derivative thereof.
Claim 8
Dependent Claim
22 words
The method in accordance with claim 5 wherein the ferroelectric material is Bi 4 Ti 3 O 12 or a derivative thereof.
Claim 9
Dependent Claim
14 words
The method in accordance with claim 2 wherein the dielectric is a perovskite material.
Claim 10
Dependent Claim
33 words
The method in accordance with claim 1 wherein the first thin film is capable of being transformed into a ferroelectric film by annealing at a temperature with in the range of 600-800° C.
Claim 11
Dependent Claim
26 words
The method in accordance with claim 1 wherein the electrically conductive material is selected from the group consisting of noble metals, metal oxides and metal nitrides.
Claim 12
Dependent Claim
19 words
The method in accordance with claim 1 wherein the electrically conductive material has been roughened by reactive ion etching.
Claim 13
Dependent Claim
24 words
The method in accordance with claim 1 wherein the surface properties of the electrically conductive material have been altered by changing its surface chemistry.
Claim 14
Dependent Claim
29 words
The method in accordance with claim 1 wherein the chemical nature of the substrate has been altered prior to chemical vapor deposition by exposing the substrate to chemical agents.
Claim 15
Dependent Claim
13 words
The method in accordance with claim 13 wherein the chemical agents are gaseous.
Claim 16
Dependent Claim
13 words
The method in accordance with claim 13 wherein the chemical agents are liquids.
Claim 17
Dependent Claim
23 words
The method in accordance with claim 13 wherein the substrate in the chamber is exposed to the chemical agents before chemical vapor deposition.
Claim 18
Dependent Claim
27 words
The method in accordance with claim 13 wherein the chemical agents are selected from the group consisting of alcohols, alkanes, alkenes, aromatics, amines and strong oxidizing agents.
Claim 19
Dependent Claim
24 words
The method in accordance with claim 1 wherein the electrically conductive material has been roughened to an initial surface roughness greater than 6 nm.
Claim 20
Dependent Claim
19 words
The method in accordance with claim 1 wherein the electrically conductive material has been roughened by inert ion mulling.
Claim 21
Dependent Claim
19 words
The method in accordance with claim 1 wherein the electrically conductive material has been roughened by chemical mechanical polishing.
Claim 22
Dependent Claim
18 words
The method in accordance with claim 1 wherein the electrically conductive material has been roughened by chemical etching.
Claim 23
Dependent Claim
19 words
The method in accordance with claim 1 wherein the electrically conductive material has been roughened by chemicals in solutions.
Claim 24
Dependent Claim
24 words
The method in accordance with claim 12 wherein the surface chemistry has been changed by depositing a second material upon the electrically conductive material.
Claim 25
Dependent Claim
24 words
The method in accordance with claim 23 wherein the second material is selected from the group consisting of iridium, titanium, tantalum, strontium or bismuth.
Claim 26
Dependent Claim
15 words
The method in accordance with claim 23 wherein the second material is deposited by sputtering.
Claim 27
Dependent Claim
14 words
The method in accordance with claim 10 wherein the electrically conductive material is platinum.
Claim 28
Dependent Claim
25 words
The method in accordance with claim 10 wherein the electrically conductive material is an alloy comprising 90% by weight platinum and 10% by weight iridium.
Claim 29
Dependent Claim
37 words
The method in accordance with claim 1 wherein the metal-organic precursor is selected from the group consisting of triphenyl bismuth, tritolyl bismuth, bismuth alkyl, bismuth alkoxides, bismuth β-diketonates, bismuth amides, mixed ligand bismuth compound and mixtures thereof.
Claim 30
Dependent Claim
26 words
The method in accordance with claim 1 wherein the precursors comprise a mixture of Strontium 2,2,6,6-tetramethylheptane-3,5-dionate as tetraglyme adduct, triphenyl bismuth and tantalum 2,2,6,6-tetramethylheptane-3,5-dionate tetrakis (isopropoxide).
Claim 31
Dependent Claim
43 words
The method in accordance with claim 1 wherein the first thin film is SrBi 2 Ta 2 O 9 and the first thin film is subjected to a high temperature anneal in the presence of oxygen at a temperature ranging from 600-820° C.
Claim 32
Dependent Claim
20 words
The method in accordance with claim 1 wherein the electrically conductive material has been roughened prior to chemical vapor deposition.
Claim 33
Dependent Claim
20 words
The method in accordance with claim 10 wherein the noble metal is chemically modified by the use of seed layers.
Claim 34
Dependent Claim
20 words
The method in accordance with claim 1 wherein the substrate is pre-annealed prior to deposition in order to roughen it.
Claim 35
Dependent Claim
19 words
The method in accordance with claim 33 wherein pre-annealing is effected in situ in the chemical vapor deposition apparatus.
Claim 36
Dependent Claim
21 words
The method in accordance with claim 33 wherein pre-annealing is effected at a temperature employed in the chemical vapor deposition apparatus.
Claim 37
Dependent Claim
13 words
The method in accordance with claim 1 wherein the metal-organic precursor comprises bismuth.
Claim 38
Dependent Claim
61 words
The method in accordance with claim 1 wherein the electrically conductive material has been pretreated by one of the techniques selected from the group consisting of: reactive ion etching; inert ion milling; chemical mechanical polishing; use of seed layers; partially reactive adhesion barrier layer; formation of noble metal alloys; chemical pretreatment; treatment with chemicals in liquid solutions and varying deposition conditions.
Claim 39
Independent Claim
143 words
A method for the nucleation controlled deposition of thin films suitable for use as the dielectric of a capacitor on a substrate member by metal-organic chemical vapor deposition which comprises the steps of: (a) placing the substrate member in a chemical vapor deposition apparatus, the substrate having deposited upon a portion thereof a film of an electrically conductive material, wherein the electrically conductive material has been pretreated; (b) heating the substrate to an elevated temperature in the range of from about 300° C. to 800° C. within the apparatus; (c) introducing vaporized metal-organic precursors carried by an inert gas into the apparatus, and thermally decomposing the precursors to substantially simultaneously yield a first in film of a homogenous composition upon the electrically conductive material, and a second thin film of a composition different from the first thin film upon the exposed substrate surface.
Claim 40
Independent Claim
143 words
A method for the nucleation controlled deposition of thin films suitable for use as the dielectric of a capacitor on a substrate member by metal-organic chemical vapor deposition which comprises the steps of: (a) placing the substrate member in a chemical vapor deposition apparatus, the substrate having deposited upon a portion thereof a film of an electrically conductive material, wherein the electrically conductive material has been pretreated; (b) heating the substrate to an elevated temperature in the range of from about 300° C. to 800° C. within the apparatus; (c) introducing vaporized metal-organic precursors carried by an inert gas into the apparatus, and thermally decomposing the precursors to substantially simultaneously yield a first in film of a homogenous composition upon the electrically conductive material, and a second thin film of a composition different from the first thin film upon the exposed substrate surface.
Claim 41
Independent Claim
137 words
A method for the nucleation controlled deposition of thin films suitable for use as the dielectric of a capacitor on a substrate member by metal-organic chemical vapor deposition which comprises the steps of: (a) placing the substrate member in a chemical vapor deposition apparatus, the substrate having deposited upon a portion thereof a film of an electrically conductive material; (b) heating the substrate to an elevated temperature in the range of from about 300° C. to 800° C. within the apparatus; (c) introducing vaporized metal-organic precursors carried by an inert gas into the apparatus, and thermally decomposing the precursors to substantially simultaneously yield a first thin film of a homogeous morphology and composition upon the electrically conductive material, and a second thin film of a composition different from the first thin film upon the exposed substrate surface.
Claim 42
Independent Claim
137 words
A method for the nucleation controlled deposition of thin films suitable for use as the dielectric of a capacitor on a substrate member by metal-organic chemical vapor deposition which comprises the steps of: (a) placing the substrate member in a chemical vapor deposition apparatus, the substrate having deposited upon a portion thereof a film of an electrically conductive material; (b) heating the substrate to an elevated temperature in the range of from about 300° C. to 800° C. within the apparatus; (c) introducing vaporized metal-organic precursors carried by an inert gas into the apparatus, and thermally decomposing the precursors to substantially simultaneously yield a first thin film of a homogeous morphology and composition upon the electrically conductive material, and a second thin film of a composition different from the first thin film upon the exposed substrate surface.
Claim 43
Dependent Claim
28 words
The method in accordance with claim 39 wherein the electrically conductive material has been roughened by the use of a plasma at the inception of the CVD process.
Claim 44
Independent Claim
27 words
The method in accordance with 39 wherein the electrically conductive material has been roughened by the use of ultraviolet activation at the inception of the CVD process.
Claim 45
Independent Claim
27 words
The method in accordance with 39 wherein the electrically conductive material has been roughened by the use of ultraviolet activation at the inception of the CVD process.
Claim 46
Dependent Claim
29 words
The method in accordance with claim 39 wherein the electrically conductive material has been roughened by the use of strong oxidizing agents at the inception of the CVD process.
Claim 47
Dependent Claim
28 words
The method in accordance with claim 39 wherein the electrically conductive material has been roughened by the use of reducing agents at the inception of the CVD process.
Claim 48
Dependent Claim
31 words
The method in accordance with claim 40 wherein the oxidizing agents are selected from the group consisting of NO, NO 2 , H 2 O 2 , and O 3 .
Claim 49
Dependent Claim
30 words
The method in accordance with claim 43 wherein the reducing agents are selected from the group consisting of H 2 , NH 3 , N 2 H 4 and alcohols.
References Cited (Backward Citations)
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