EP1124262A2
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EP
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Multilayer dielectric stack and method
Assignee: Sharp Corp
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Filing: 2001-02-08
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Granted: —
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Expires: 2021-02-08
Abstract
Abstract A multilayer dielectric stack is provided which has alternating layers of a high-k material and an interposing material. The presence of the interposing material and the thinness of the high-k material layers reduces or eliminate effects of crystallization within the high-k material, even at relatively high annealing temperatures. The high-k dielectric layers are a metal oxide of preferably zirconium or hafnium. The interposing layers are preferably amorphous aluminum oxide, aluminum nitride, or silicon nitride. Because the layers reduce the effects of crystalline structures within individual layers, the overall tunneling current is reduced. Also provided are atomic layer deposition, sputtering, and evaporation as methods of depositing desired materials for forming the above-mentioned multilayer dielectric stack.
Inventors
- 👤 Yanjun Ma
- 👤 Yoshi Ono
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 00:54
CPC Classifications
H; H10; H10P; H10P10/00; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01332; H10D64/01336; H10D64/0134; H10D30/00; H10D30/01; H10D30/021; H10D30/0223; H10D30/0225; H10D64/01342; H10D64/60; H10D64/66; H10D64/68; H10D64/681; H10D64/685; H10D64/01344; H10D64/691; H10D64/693
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
67 words
A MOS transistor comprising: a) a gate electrode; b) a channel region having a top surface underlying the
gate electrode; and c) a gate dielectric stack, which comprises a first
dielectric layer comprising a first dielectric material, a second dielectric
layer comprising a second dielectric material, and a third dielectric layer
comprising the first dielectric material, interposed between the gate
electrode and the channel region top surface.
Claim 2
Dependent Claim
69 words
An integrated circuit (IC) structure for an IC
comprising a multilayer dielectric stack comprising: a) a first dielectric layer comprising a first dielectric
material overlying a semiconductor substrate ; b) a second dielectric layer comprising a second dielectric
material overlying the first dielectric layer; c) a third dielectric layer comprising the first dielectric
material overlying the first and second dielectric layers; and d) an electrode overlying the dielectric stack.
Claim 3
Dependent Claim
62 words
The integrated circuit structure as in claim 2, wherein
the first dielectric material is selected from the group consisting of ZrO 2 ,
HfO 2 , TiO 2 , and Ta 2 O 5 , and the second dielectric material is selected from
the group consisting of Al 2 O 3 , AlN, SiN, Si 3 N 4 and SiO 2 .
Claim 4
Dependent Claim
62 words
The integrated circuit structure as in claim 2, wherein
the first dielectric material is selected from the group consisting of Al 2 O 3 ,
AlN, SiN, Si 3 N 4 and SiO 2 , and the second dielectric material is selected
from the group consisting of ZrO 2 , HfO 2 , TiO 2 , and Ta 2 O 5 .
Claim 5
Dependent Claim
19 words
The integrated circuit structure as in claim 2, wherein
the first dielectric layer is less than 50 angstroms thick.
Claim 6
Dependent Claim
21 words
The integrated circuit structure as in claim 2, wherein
the first dielectric layer is between approximately 2 and 5 angstroms
thick.
Claim 7
Dependent Claim
19 words
The integrated circuit structure as in claim 2, wherein
the second dielectric layer is less than 50 angstroms thick.
Claim 8
Dependent Claim
21 words
The integrated circuit structure as in claim 2, wherein
the second dielectric layer is between approximately 2 and 5 angstroms
thick.
Claim 9
Dependent Claim
23 words
The integrated circuit structure as in claim 2, further
comprising an oxidation barrier interposed between the first dielectric
layer and the semiconductor substrate.
Claim 10
Dependent Claim
27 words
The integrated circuit structure as in claim 9,
wherein the oxidation barrier is composed of material selected from the
group consisting of silicon nitride and silicon oxynitride.
Claim 11
Dependent Claim
33 words
The integrated circuit structure as in claim 2, wherein
a plurality of alternating layers of the first dielectric material and the
second dielectric material are interposed between the semiconductor
substrate and the electrode.
Claim 12
Dependent Claim
26 words
The integrated circuit structure as in claim 11,
wherein the plurality of alternating layers has a combined thickness of
between approximately 20 and 200 angstroms thick.
Claim 13
Independent Claim
63 words
A method of forming a dielectric stack comprising the
steps of: a) forming a first dielectric layer on an upper surface of a
semiconductor substrate; b) forming a second dielectric layer on the first dielectric
layer; and c) forming a third dielectric layer above the second
dielectric layer, wherein the third dielectric layer comprises the same
dielectric material as the first dielectric material.
Claim 14
Dependent Claim
29 words
The method of claim 13,further comprising the step of
annealing the semiconductor substrate at a temperature between
approximately 400 and 900 degrees Celsius, whereby the dielectric stack
is conditioned.
Claim 15
Dependent Claim
36 words
The method of claim 14,further comprising the step of
depositing an electrode layer over the dielectric stack and the step of
patterning the electrode layer and underlying dielectric stack to form a
desired integrated circuit structure.
Claim 16
Independent Claim
26 words
The method of claim13, wherein the step of forming
the first dielectric layer uses atomic layer deposition to deposit a layer of
the first dielectric material.
Claim 17
Independent Claim
26 words
The method of claim13, wherein the step of forming
the second dielectric layer uses atomic layer deposition to deposit a layer
of the second dielectric material.
Claim 18
Independent Claim
28 words
The method of claim13, wherein the step of forming
the first dielectric layer uses atomic layer deposition to deposit of a first
precursor of the first dielectric material
Claim 19
Independent Claim
19 words
The method of claim18, further comprising the step of
oxidizing the first precursor to form the first dielectric material.
Claim 20
Dependent Claim
15 words
The method of claim 18, wherein the first precursor is
deposited as a self-limiting monolayer.
Claim 21
Dependent Claim
25 words
The method of claim 18, wherein the first precursor is
selected from the group consisting of ZrCl 4 , Zr(iOPr) 4 and Zr(tmhd) 4 .
Claim 22
Dependent Claim
44 words
The method of claim 13, wherein the step of forming
the first dielectric layer uses sputtering of a first target for a
predetermined duration and the step of forming the second dielectric layer
uses pulsed sputtering of a second target for a predetermined duration.
Claim 23
Dependent Claim
21 words
The method of claim 22, wherein the duration of
sputtering the first target and the second target is controlled by shutters.
Claim 24
Dependent Claim
13 words
The method of claim 22, wherein sputtering is
performed in an oxidizing atmosphere.
Claim 25
Dependent Claim
45 words
The method of claim 13, wherein the step of forming
the first dielectric layer uses evaporation of a first target material for a
predetermined duration and the step of forming the second dielectric layer
uses evaporation of a second target material for a predetermined duration
Claim 26
Dependent Claim
22 words
The method of claim 25, wherein the duration of
evaporation of the first target and the second target is controlled by
shutters.
Claim 27
Dependent Claim
64 words
A MOS transistor, the structure of which includes a gate dielectric
stack disposed between a channel region and a gate electrode above the channel
region, the stack including a first dielectric layer comprising a first dielectric material
and a second dielectric layer comprising a second, different dielectric material, the
first dielectric material having a dielectric constant higher than that of the second
dielectric material.
Claim 28
Dependent Claim
45 words
A MOS transistor according to claim 27, wherein the gate dielectric
stack includes a third dielectric layer comprising a dielectric material having a
dielectric constant higher than that of the second dielectric material, the second
dielectric layer lying between the first and second dielectric layers.
Claim 29
Dependent Claim
24 words
A MOS transistor according to claim 28, wherein the dielectric
material of the third dielectric layer is the same as the first dielectric material.
Claim 30
Dependent Claim
52 words
A MOS transistor according to claim 27, wherein the gate dielectric
stack includes a third dielectric layer comprising a third dielectric material, the
dielectric constant of the first dielectric material being higher than that of the third
dielectric material, and the first dielectric layer lying between the second and third
dielectric layers.
Claim 31
Dependent Claim
20 words
A MOS transistor according to claim 30, wherein the third dielectric
material is the same as the second dielectric material.
References Cited (Backward Citations)
No citation records indexed.
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