[PPT] - Stabilizing Cubic HfO 2 Doped Y 2 O 3 using TEM Stabilizing Cubic HfO PowerPoint Presentation

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UIC Physics

APS March Meeting 2008

Stabilizing Cubic HfO2 Doped Y2O3 using TEM Stabilizing Cubic HfO2 Doped Y2O3 using TEM Peter Gu, W. Walkosz, R.F. Klie Nanoscale Physics Group University of Illinois at Chicago

http://www.tedpella.com/grids_html/si-window.jpg

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UIC Physics

APS March Meeting 2008

Moore’s Law Moore’s Law

1965 by Intel

cofounder, Gordon Moore

Exponential

increase in transistor density

Limit to trend
SiO2 (2 nm –

breakdown)

Criteria
Insulating
Thermally Stable
Chemically Stable
High κ materials
http://www.developers.net/storyImages/062404/inteldemystifying1.jpg

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UIC Physics

APS March Meeting 2008

XRD-data XRD-data

Image from professor Takoudis’ group

GI-XRD 2.5% Y in HfO2 annealed at different temperatures

100 200 300 400 500 600 700 800 900 1000 10 20 30 40 50 60 70

2 Theta Intensity

tetra.-HfO2 cubic-HfO2 monclinic-HfO2 925 C 800 C 600 C

(111) (200) (220) (311) (101) (002) (110) (112) (200) (103) (211) (222)

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UIC Physics

APS March Meeting 2008

XRD-data XRD-data

GI-XRD 20% Y in HfO2 annealed at different temperatures

100 200 300 400 500 600 700 800 900 1000 10 20 30 40 50 60 70

2 Theta Intensity

tetra.-HfO2 cubic-HfO2 monclinic-HfO2 925 C 800 C 600 C

(111) (200) (220) (311) (222) (101) (002) (110) (112)(200) (103)(211)

Image from professor Takoudis’ group

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APS March Meeting 2008

κ vs Yttrium Concentration κ vs Yttrium Concentration

Image from professor Takoudis’ group
% Yttrium

concentration measured via XPS

κ measured via CV
Local Max ~ 20%

Yttrium

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APS March Meeting 2008

Research Plan Research Plan

Samples:
Annealed 2.5% Y2O3 on HfO2
Unannealed 2.5% Y2O3 on HfO2
Annealed 20% Y2O3 on HfO2
TEM 3010
Diffraction mode
Check crystal structure – polymorphs (cubic vs. tetragonal vs. monoclinic)
Check for homogeneity
SiO2 layer thickness
Grain Size
Journal of Applied Physics 103, 084103 (2008)

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UIC Physics

APS March Meeting 2008

2.5% Y2O3 Un-Annealed 2.5% Y2O3 Un-Annealed

Image at 150,000 Magnification 2.5% Yttrium Oxide / Hafnium Oxide Un-Annealed Sample Silicon Substrate Silicon Dioxide Hafnia / Yttria film

layers

Epoxy

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UIC Physics

APS March Meeting 2008

2.5% Y2O3 Un-Annealed - Diffraction 2.5% Y2O3 Un-Annealed - Diffraction

Image at 50 cm Camera Length 2.5% Yttrium Oxide / Hafnium Oxide Un-Annealed Sample

Superimposed Patterns
Spot Pattern – Silicon Substrate (001)
Cubic structure
Fuzzy circular – Film
Amorphous

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UIC Physics

APS March Meeting 2008

2.5% Y2O3 Annealed 2.5% Y2O3 Annealed

Image at 600,000 Magnification 2.5% Yttrium Oxide / Hafnium Oxide Annealed Sample Silicon Substrate Silicon Dioxide Hafnia / Yttria film Epoxy

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UIC Physics

APS March Meeting 2008

2.5% Y2O3 Annealed - Diffraction 2.5% Y2O3 Annealed - Diffraction

Image at 50 cm Camera Length 2.5% Yttrium Oxide / Hafnium Oxide Annealed Sample

Superimposed Patterns
Spot Pattern – Silicon Substrate (001)
Cubic structure
Concentric Circular pattern– Film
Cubic Hafnium Oxide

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UIC Physics

APS March Meeting 2008

20% Y2O3 Annealed 20% Y2O3 Annealed

Image at 500,000 Magnification 20% Yttrium Oxide / Hafnium Oxide Annealed Sample Epoxy Hafnia / Yttria film Silicon Dioxide Silicon Substrate

SLIDE 12

UIC Physics

APS March Meeting 2008

20% Y2O3 Annealed - Diffraction 20% Y2O3 Annealed - Diffraction

Image at 50 cm Camera Length 20% Yttrium Oxide / Hafnium Oxide Annealed Sample

Superimposed Patterns
Spot Pattern – Silicon

Substrate (001)

Cubic structure
Concentric Circular

pattern– Film

Cubic Hafnium

Oxide (0,0,0)Si (2,0,0)Si (-2,0,0)Si (4,0,0)Si (-4,0,0)Si (1,1,-1)Si (-1,1,-1)Si (-1,-1,1)Si (1,-1,1)Si

(3,-1,1)Si

(-3,-1,1)Si (3,1,-1)Si (-3,1,-1)Si (0,2,-2)Si (0,-2,2)Si (2,-2,2)Si (-2,-2,2)Si (-2,2,-2)Si (-1,3,-3)Si (1,-3,3)Si (-1,-3,3)Si (0,-4,4)Si (-3,-3,3)Si (-4,-2,2)Si (-5,-1,1)Si (1,1,1)HfO2 (2,0,0)HfO2 (1,1,3)HfO2

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APS March Meeting 2008

SiO2 Layer Analysis SiO2 Layer Analysis

Expected for 30 nm film thickness:
~3 nm for 20% Y2O3
~12 nm for 2.5% Y2O3
Silicon Dioxide Layer Analysis

2.5% Y2O3 unannealed(nm) 2.5% Y2O3 annealed(nm) 20% Y2O3 annealed(nm) average 2.289 3.072 3.175 max 3.845 5.774 4.2 min 0.939 1.303 0.765 stdev 0.875 1.332 0.759

2 2 2

+ constant SiO layer thickness film layer thickness SiO layer thickness film layer thickness film dielectric SiO dielectric constant total dielectric constant + =

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APS March Meeting 2008

Grain Size Analysis Grain Size Analysis

Grain Size Measurements - 20% annealed sample Grain Size Measurements - 2.5% annealed sample Along Grain (nm) Perpendicular to Grain (nm) Along Grain (nm) Perpendicular to Grain (nm)

Average (nm) 4.339 5.510 5.705 5.069 Standard Dev. 0.833 1.217 1.007 1.507

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APS March Meeting 2008

Summary / Conclusion Summary / Conclusion

20% Annealed Sample has a larger

dielectric constant than 2.5% Annealed Sample

No Difference in Structural makeup of

interfacial film (Both cubic polymorph)

No Difference in Silicon Dioxide Layer

Thickness

No Difference in Grain Size
Difference in film shape or thickness?
Difference in Oxygen Concentration?

SLIDE 16

UIC Physics

APS March Meeting 2008

Acknowledgements Acknowledgements

National Science Foundation
Grant NSF EEC 0755115
NSF CMS 0829903
Department of Defense
Professor R.F. Klie
Professor C. Takoudis
Professor G. Jursich
PhD G. Yang
PhD Q. Tao
Weronica Walkosz
Ke-Bin Low
K.C. Kragh

SLIDE 17

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APS March Meeting 2008

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