Transcript Alloy Thin Films by Multi

Alloy Thin Films by Multi-Target
Sputtering
Karla L. Perez
MSE/REU
Final Presentation
Adv. Prof. King and Prof. Dayananda
August 5, 2004
Overview
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Introduction
Research Project
Processing
Measuring Film Thickness
– Optical Microscope
– AFM
• Alloy Thin Film Deposition
– Composition
• Conclusion
Application of Thin Films
• Antireflection coatings for camera
lenses
• Optical filters for communication
• Decorative coatings on plastics
• Silicon chips
• Metallic coatings
• To provide insulating layers between
conductors
Research Project
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The main goal is to create alloy thin films with uniform composition
and thickness
Study the compositions of pure metal thin films and their thickness
Pure metal components to be used: Ag, Cu, Ta, Mo, Ni, Fe, Ti
Design a system which will enable us to manage the composition
and geometry of the alloy thin films
Processing
• Sputtering
It is a type of Physical Vapor
Deposition. It is carried out
at high vacuum in a
chamber connected to a
high voltage DC supply.
Argon gas is pumped into
the chamber and creates
argon plasma. The Argon
plasma is directed to the
target and its atoms are
vaporized. The vaporized
material is then deposited
on the substrate.
Measuring Film Thickness
• Optical Microscope
– Differential Interference Contrast (DIC)
Ag 20min 4cm
Measuring Film Thickness
Optical Microscope
Cu 10min 4cm
Ag 20min 4cm
Measuring Film Thickness
Optical Microscope
Ag 10 min 4cm
Ag 20min 4cm
Measuring Film Thickness
• Atomic Force Microscope (AFM)
– Tapping mode: Measures the topography by
tapping the surface with an oscillating tip. This
eliminates the shear forces which can damage soft
samples and reduce image resolution.
Measuring Film Thickness
Measuring Film Thickness
AFM
Ag 20min 2cm
Measuring Film Thickness
AFM
Mo 30min 2cm
Measuring Film Thickness
AFM
Cu 30min 2cm
Ag 30min 2cm
Number of Unit Cells Deposited per Minute
60
50
Time
40
30
52.40
14.19
Number of Cells Deposited
per Minute
20
10
0
1
2
3
5
6
9
10 11 12 13 14 15 16
Position on slide
Alloy Thin Film Deposition
• Deposit alloy thin films using a sputter
coater with a Copper-Silver target
Composition of Ag-Cu Thin Film
Ag-Cu composition
100
90
92.7%
80
mole wt%
70
60
50.3%
50
Ag
Cu
40
30
20
7.3%
10
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17
Position
on in
slide
Position
slide
Composition of Ag-Cu Thin Film
Ag-Cu concentration wt%
120
100
concentration wt%
95.6%
50.3%
80
Ag
60
Cu
40
20
4.4%
0
1
2
3
4
5
6
7
8
9
10
11
Position on
slide
Position
in slide
12
13
14
15
16
17
Conclusion
• The thickness of the film varies
according to their position relative to
the target.
• Films deposited are thicker in the
middle.
• Deposited one alloy thin film
• The same composition gradients of
silver and copper do not occur in the
middle of the film.
Acknowledgements
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Prof. King
Prof. Dayananda
Prof. Kvam
NSF Grant
Questions???
Thank you!!!