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US6780704B1
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Conformal thin films over textured capacitor electrodes
Assignee: ASM International NV
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Filing: 1999-12-03
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Granted: 2004-08-24
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Expires: 2019-12-03
Abstract
Abstract Method and structures are provided for conformal capacitor dielectrics over textured silicon electrodes for integrated memory cells. Capacitor structures and first electrodes or plates are formed above or within semiconductor substrates. The first electrodes include hemispherical grain (HSG) silicon for increasing the capacitor plate surface area. The HSG topography is then exposed to alternating chemistries to form monolayers of a desired dielectric material. Exemplary process flows include alternately pulsed metal organic and oxygen source gases injected into a constant carrier flow. Self-terminated metal layers are thus reacted with oxygen. Near perfect step coverage allows minimal thickness for a capacitor dielectric, given leakage concerns for particular materials, thereby maximizing the capacitance for the memory cell and increasing cell reliability for a given memory cell design. Alternately pulsed chemistries are also provided for depositing top electrode materials with continuous coverage of capacitor dielectric, realizing the full capacitance benefits of the underlying textured morphology.
Inventors
- 👤 Ivo Raaijmakers
- 👤 Suvi P. Haukka
- 👤 Ernst H. A. Granneman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:42
CPC Classifications
H; H10; H10B; H10B12/00; H10D; H10D1/00; H10D1/60; H10D1/68; H10P; H10P14/00; H10P14/60; H10P14/65; H10P14/6502; H10P14/6506; H10P14/66; H10P14/662; H10P14/69; H10P14/692; H10P14/6921; H10P14/6928; H10P14/6934; H10P14/6938; H10P14/6939; H10P14/69391; H10P14/69393; H10P14/69394; H10P14/69395; H10B12/01; H10B12/02; H10B12/03; H10B12/033; H10B12/038; H10D1/692; H10D1/711; H10D1/712; H10P14/63; H10P14/6326; H10P14/6328; H10P14/6334; H10P14/6339; Y; Y10; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 46
Claim 1
Independent Claim
121 words
A method of forming a capacitor in an integrated circuit, comprising: constructing a bottom electrode including a textured silicon layer, the textured silicon layer having hemispherical grain (HSG) morphology; and depositing a high k dielectric layer directly over the textured silicon layer wherein depositing comprises: forming no more than about one monolayer of a first material over the textured silicon layer by exposure to a first reactant species; reacting a second reactant species with the first material to leave no more than about one monolayer of a second material; and exposing the second material to a third reactant species to leave no more than about one monolayer of a third material, wherein the dielectric layer comprises two different metals and oxygen.
Claim 2
Independent Claim
121 words
A method of forming a capacitor in an integrated circuit, comprising: constructing a bottom electrode including a textured silicon layer, the textured silicon layer having hemispherical grain (HSG) morphology; and depositing a high k dielectric layer directly over the textured silicon layer wherein depositing comprises: forming no more than about one monolayer of a first material over the textured silicon layer by exposure to a first reactant species; reacting a second reactant species with the first material to leave no more than about one monolayer of a second material; and exposing the second material to a third reactant species to leave no more than about one monolayer of a third material, wherein the dielectric layer comprises two different metals and oxygen.
Claim 3
Dependent Claim
50 words
The method of claim 1 , wherein forming no more than about one monolayer comprises supplying a first chemistry substantially excluding the second reactant species, reacting comprises supplying a second chemistry substantially excluding the first reactant species and exposing comprises supplying a third chemistry substantially excluding the second reactant species.
Claim 4
Dependent Claim
38 words
The method of claim 2 , further comprising repeatedly alternating supplying the first chemistry, supplying the second chemistry and supplying the third chemistry until a dielectric layer forms having a thickness between about 10 Å and 200 Å.
Claim 5
Dependent Claim
28 words
The method of claim 2 , further comprising supplying a carrier gas while repeatedly alternating supplying the first chemistry, supplying the second chemistry and supplying the third chemistry.
Claim 6
Dependent Claim
33 words
The method of claim 4 , wherein the carrier gas purges reactants between supplying the first chemistry and supplying the second chemistry and between supplying the second chemistry and supplying the third chemistry.
Claim 7
Dependent Claim
34 words
The method of claim 5 , wherein supplying the first chemistry is stopped and the reaction chamber is purged with more than about two chamber volumes of purge gas before supplying the second chemistry.
Claim 8
Dependent Claim
16 words
The method of claim 1 , wherein the dielectric layer comprises a metal, silicon and oxygen.
Claim 9
Dependent Claim
19 words
The method of claim 1 , wherein the dielectric layer has a dielectric constant of greater than about 10.
Claim 10
Dependent Claim
21 words
The method of claim 8 , wherein the dielectric layer has a dielectric constant equal to or greater than about 20.
Claim 11
Dependent Claim
12 words
The method of claim 1 , wherein the first material is self-terminated.
Claim 12
Dependent Claim
15 words
The method of claim 10 , wherein the first material is terminated by halide ligands.
Claim 13
Dependent Claim
15 words
The method of claim 10 , wherein the first material is terminated by organic ligands.
Claim 14
Dependent Claim
27 words
The method of claim 1 , further comprising forming a barrier layer directly on the textured silicon surface prior to forming no more than about one monolayer.
Claim 15
Dependent Claim
17 words
The method of claim 13 , wherein forming a barrier layer comprises nitriding the textured silicon surface.
Claim 16
Dependent Claim
27 words
The method of claim 13 , wherein forming a barrier layer comprises oxidizing the textured silicon surface to form a silicon oxide and nitriding the silicon oxide.
Claim 17
Dependent Claim
15 words
The method of claim 1 , wherein bottom electrode conforms to a three-dimensional folding structure.
Claim 18
Dependent Claim
18 words
The method of claim 16 , wherein the bottom electrode conforms to a trench within a semiconductor substrate.
Claim 19
Dependent Claim
17 words
The method of claim 16 , wherein the three-dimensional folding shape is formed above a semiconductor substrate.
Claim 20
Dependent Claim
14 words
The method of claim 18 , wherein the three-dimensional shape defines an interior volume.
Claim 21
Dependent Claim
14 words
The method of claim 19 , wherein the three-dimensional shape conforms to a cylinder.
Claim 22
Dependent Claim
66 words
The method of claim 1 , further comprising depositing a conductive layer over the dielectric layer, wherein depositing the conductive layer comprises: forming no more than about one monolayer of a fourth material over the dielectric layer by exposure to a fourth reactant species; and reacting a fifth reactant species with the fourth material to leave no more than about one monolayer of a fifth material.
Claim 23
Dependent Claim
32 words
The method of claim 21 , wherein the fourth reactant species comprises a metal complex, the fifth reactant species comprises a nitrogen-containing source gas, and the conductive layer comprises a metal nitride.
Claim 24
Independent Claim
117 words
A method of forming a capacitor in an integrated circuit, comprising: constructing a bottom electrode including a textured silicon layer, the textured silicon layer having hemispherical grain (HSG) morphology; and depositing a high k dielectric layer directly over the textured silicon layer wherein depositing comprises: forming no more than about one monolayer of a first material over the textured silicon layer by exposure to a first reactant species, the first material being self-terminated with halide ligands; and reacting a second reactant species with the first material to leave no more than about one monolayer of a second material, wherein the first reactant species comprises a zirconium halide and the second reactant species comprises an oxygen-containing source gas.
Claim 25
Independent Claim
117 words
A method of forming a capacitor in an integrated circuit, comprising: constructing a bottom electrode including a textured silicon layer, the textured silicon layer having hemispherical grain (HSG) morphology; and depositing a high k dielectric layer directly over the textured silicon layer wherein depositing comprises: forming no more than about one monolayer of a first material over the textured silicon layer by exposure to a first reactant species, the first material being self-terminated with halide ligands; and reacting a second reactant species with the first material to leave no more than about one monolayer of a second material, wherein the first reactant species comprises a zirconium halide and the second reactant species comprises an oxygen-containing source gas.
Claim 26
Independent Claim
115 words
A method of forming a capacitor in an integrated circuit, comprising: constructing a bottom electrode including a textured silicon layer, the textured silicon layer having hemispherical grain (HSG) morphology; and depositing a high k dielectric layer directly over the textured silicon layer wherein depositing comprises: forming no more than about one monolayer of a first material over the textured silicon layer by exposure to a first reactant species, the first material being self-terminated with halide ligands; and reacting a second reactant species with the first material to leave no more than about one monolayer of a second material, wherein the first material comprises ethoxide-terminated tantalum and the second reactant species comprises an oxygen-containing source gas.
Claim 27
Independent Claim
115 words
A method of forming a capacitor in an integrated circuit, comprising: constructing a bottom electrode including a textured silicon layer, the textured silicon layer having hemispherical grain (HSG) morphology; and depositing a high k dielectric layer directly over the textured silicon layer wherein depositing comprises: forming no more than about one monolayer of a first material over the textured silicon layer by exposure to a first reactant species, the first material being self-terminated with halide ligands; and reacting a second reactant species with the first material to leave no more than about one monolayer of a second material, wherein the first material comprises ethoxide-terminated tantalum and the second reactant species comprises an oxygen-containing source gas.
Claim 28
Independent Claim
88 words
A method of forming a dielectric layer having a dielectric constant greater than or equal to about 20 directly over a textured silicon bottom electrode having a hemispherical grain (HSG) morphology in an integrated circuit, comprising: forming no more than about one monolayer of a metal-containing species in a self-limited reaction directly over the textured silicon bottom electrode having a hemispherical grain (HSG) morphology; and reacting an oxygen-containing species with the monolayer to form the dielectric layer having a dielectric constant greater than or equal to about 20.
Claim 29
Independent Claim
88 words
A method of forming a dielectric layer having a dielectric constant greater than or equal to about 20 directly over a textured silicon bottom electrode having a hemispherical grain (HSG) morphology in an integrated circuit, comprising: forming no more than about one monolayer of a metal-containing species in a self-limited reaction directly over the textured silicon bottom electrode having a hemispherical grain (HSG) morphology; and reacting an oxygen-containing species with the monolayer to form the dielectric layer having a dielectric constant greater than or equal to about 20.
Claim 30
Dependent Claim
16 words
The method of claim 25 , wherein the self-limited reaction comprises forming a halogen-terminated metal film.
Claim 31
Dependent Claim
15 words
The method of claim 26 , wherein reacting the oxygen-containing species comprises a ligand-exchange reaction.
Claim 32
Dependent Claim
34 words
The method of claim 25 , further comprising repeating forming no more than about one monolayer and reacting the oxygen-containing species at least about 10 times until the dielectric layer has a desired thickness.
Claim 33
Dependent Claim
96 words
A process of forming a capacitor dielectric having a dielectric constant of greater than or equal to about 20 over a hemispherical grain silicon surface, comprising: directly coating the hemispherical grain silicon surface with no more than about one monolayer of a ligand-terminated metal complex in a first phase; replacing ligands of the ligand-terminated metal with oxygen in a second phase distinct from the first phase; and repeating the first and second phases in at least about 10 cycles to form the capacitor dielectric having a dielectric constant of greater than or equal to about 20.
Claim 34
Dependent Claim
96 words
A process of forming a capacitor dielectric having a dielectric constant of greater than or equal to about 20 over a hemispherical grain silicon surface, comprising: directly coating the hemispherical grain silicon surface with no more than about one monolayer of a ligand-terminated metal complex in a first phase; replacing ligands of the ligand-terminated metal with oxygen in a second phase distinct from the first phase; and repeating the first and second phases in at least about 10 cycles to form the capacitor dielectric having a dielectric constant of greater than or equal to about 20.
Claim 35
Dependent Claim
33 words
The process of claim 29 , wherein each cycle comprises a third phase, the third phase comprising adsorbing no more than about one monolayer of a second ligand-terminated metal after the second phase.
Claim 36
Dependent Claim
27 words
The process of claim 30 , wherein each cycle further comprises a fourth phase, the fourth phase comprising replacing ligands of the second ligand-terminated metal with oxygen.
Claim 37
Dependent Claim
16 words
The process of claim 31 , wherein the first phase comprises pulsing a first oxygen-containing species.
Claim 38
Dependent Claim
16 words
The process of claim 32 , wherein the fourth phase comprises pulsing a different oxygen-containing species.
Claim 39
Dependent Claim
15 words
The process of claim 29 , wherein the ligand-terminated metal comprises a metal chloride complex.
Claim 40
Dependent Claim
16 words
The process of claim 29 , comprising maintaining a temperature of less than about 350° C.
Claim 41
Dependent Claim
83 words
A process of forming a capacitor dielectric having a dielectric constant of about 10 over a hemispherical grain silicon surface, comprising: directly coating the hemispherical grain silicon surface with no more than about one monolayer of a ligand-terminated metal complex in a first phase; replacing ligands of the ligand-terminated metal with oxygen in a second phase distinct from the first phase; and repeating the first and second phases in at least about 10 cycles, wherein the ligand-terminated metal comprises a metal ethoxide complex.
Claim 42
Dependent Claim
83 words
A process of forming a capacitor dielectric having a dielectric constant of about 10 over a hemispherical grain silicon surface, comprising: directly coating the hemispherical grain silicon surface with no more than about one monolayer of a ligand-terminated metal complex in a first phase; replacing ligands of the ligand-terminated metal with oxygen in a second phase distinct from the first phase; and repeating the first and second phases in at least about 10 cycles, wherein the ligand-terminated metal comprises a metal ethoxide complex.
Claim 43
Independent Claim
78 words
A method of forming a capacitor with high surface area in an integrated circuit, comprising: forming a bottom electrode in a three-dimensional folding shape; superimposing a hemispherical grain silicon layer over the three-dimensional folding shape; and depositing a high k dielectric layer conformally directly over the textured morphology by cyclically supplying at least three alternating, self-terminating chemistries, wherein no more than one monolayer is formed per cycle, and wherein the dielectric layer comprises silicon, oxygen and a metal.
Claim 44
Independent Claim
78 words
A method of forming a capacitor with high surface area in an integrated circuit, comprising: forming a bottom electrode in a three-dimensional folding shape; superimposing a hemispherical grain silicon layer over the three-dimensional folding shape; and depositing a high k dielectric layer conformally directly over the textured morphology by cyclically supplying at least three alternating, self-terminating chemistries, wherein no more than one monolayer is formed per cycle, and wherein the dielectric layer comprises silicon, oxygen and a metal.
Claim 45
Independent Claim
117 words
A method of forming a capacitor in an integrated circuit, comprising: constructing a bottom electrode including a textured silicon layer, the textured silicon layer having hemispherical grain (HSG) morphology; and depositing a high k dielectric layer directly over the textured silicon layer wherein depositing comprises: forming no more than about one monolayer of a first material over the textured silicon layer by exposure to a first reactant species; and reacting a second reactant species with the first material to leave no more than about one monolayer of a second material, and wherein the dielectric layer is selected from the group consisting of tantalum oxide, titanium oxide, zirconium oxide, niobium oxide, hafnium oxide and mixtures and compounds thereof.
Claim 46
Independent Claim
117 words
A method of forming a capacitor in an integrated circuit, comprising: constructing a bottom electrode including a textured silicon layer, the textured silicon layer having hemispherical grain (HSG) morphology; and depositing a high k dielectric layer directly over the textured silicon layer wherein depositing comprises: forming no more than about one monolayer of a first material over the textured silicon layer by exposure to a first reactant species; and reacting a second reactant species with the first material to leave no more than about one monolayer of a second material, and wherein the dielectric layer is selected from the group consisting of tantalum oxide, titanium oxide, zirconium oxide, niobium oxide, hafnium oxide and mixtures and compounds thereof.
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