1. Sputtering Deposition of Metallic Thin Films
Malcolm Clark, Sachin Muley, Paul M. Voyles
Materials Science Program UW-Madison, Madison, WI, 53706, USA.
Introduction
Methods
Background
SummaryResults
Sputtering is a method of physical vapor
deposition used to deposit thin films. We have
reconditioned a used vacuum system for
sputtering deposition of metal thin films. Thin
films microstructures varies with substrate
temperature and pressure in which they are
deposited.
1. Argon gas is bled into the vacuum chamber
2. A magnetic field traps free electrons which
ionize the gas molecules
3. As a result a plasma of the gas is formed
4. A magnetic field traps free electrons which
ionize the gas molecules
5. The energetically charged ions then collide
with the target knocking off atoms
6. These atoms then coat the substrate making a
thin film
Purpose
To discover how the substrate temperature
effects the structures and properties of thin films
in order to create ultra-stable amorphous thin
films for wear coatings
Sputtering Deposition
• Used to fabricate the metallic thin films
Scanning Electron Microscope
• Used to analyze the topography and
composition of a sample by scanning it with a
focused beam of electrons
XPS – X-ray Photoelectron Spectroscopy
• Measures the elemental composition of a
material. This is used to find if there is any
contamination or impurities in the thin film
How it works
References
1. Materials Science Products. (n.d.). Retrieved from
https://www.sigmaaldrich.com/materials-science/material-science-
products.html?TablePage=108832720
2. Hoffman, D. W., & McCune, R. C. (n.d.). Microstructural Control of Plasma-Sputtered
Refractory Coatings. Handbook of Plasma Processing Technology, 483-517.
Retrieved from http://www.atechsystem.co.kr/sub1/pdf/115.pdf
3. Thornton, J. A. (1974). Influence of apparatus geometry and deposition conditions
on the structure and topography of thick sputtered coatings. J. Vac. Sci. Technol.
Journal of Vacuum Science and Technology, 11(4), 666-670. doi:10.1116/1.1312732
4. Alfonso, E., Olaya, J., & Cubillos, G. (n.d.). Thin Film Growth Through Sputtering
Technique and Its Applications. Retrieved from
http://cdn.intechopen.com/pdfs/39143/InTech-
Thin_film_growth_through_sputtering_technique_and_its_applications.pdf
Thornton Zone Diagram
Zone 1 – loose fibrous grains
Zone T – tightly packed fibrous grains
Zone 2 – full dense columnar grains
Zone 3 – recrystallization with random orientation
Future Work
Implications
1. Materials Science Products. (n.d.). Retrieved from
https://www.sigmaaldrich.com/materials-science/material-science-
products.html?TablePage=108832720
Aluminum Sample
• Aluminum films -Grow films at different
substrate temperatures
• Zinc Films – grow zinc films at different
homologous temps with the same argon
pressure and compare them to aluminum
film samples
• Explore substrate temperatures and argon
pressures that maximize the stability of thin
films
• Maintenance and upgrades of deposition
system
T/Tm ≈ .32 (room temp)
Argon Pressure 3.0 mTorr
T/Tm ≈ .3
Argon Pressure 3.0 mTorr
T/Tm ≈ .5
Argon Pressure 3.0 mTorr
T/Tm≈ .7
Argon Pressure 3.0 mTorr
Expected outcomes for continued research
Films at deposited around
these parameters will
likely have tightly dense
columnar grains that may
extended through most of
the film and a topography
that consist of domed and
faceted structures
It is reasonable for films
at this homologous
temperature and
pressure to have fully
dense columnar grains
that extend through the
entire film and to have a
surface composed of
faceted structures
A film fabricated at this
homologous temperature
and pressure is expected
to have tightly packed
fibrous grains and it
would be expected to see
smooth domed surface
Objective
To reproduce results from literature –
successful reproduction of results
ensures that the sputtering deposition
system functions properly
Plan Of Approach
To grow elemental films at different
homologous temperatures at the same
argon pressure. Then analyze the films
and compare them to results from
literature
Thornton Zone Diagram
The Thornton Zone Diagram is a schematic
showing the dependence of coating structure
of the substrate temperature and argon
pressure
Once all of the aluminum film samples are
fabricated we will be able to analyze them and
compare them to results from literature. If the
samples match the results from literature we
can confirm that the sputtering deposition
system is working properly. We can then use
the deposition system to examine substrate
temperature and argon pressures that maximize
the stability of thin films in order to create ultra-
stable amorphous thin films for wear coatings.
At Homologous
temperatures around .8 and
above will begin to
recrystallize and will have
smooth flat grains at the
surface with clear grooved
boundaries.
T/Tm≈ .8
Wear Coatings
Using sputtering deposition thin films can be
created with unique properties and structures
that make them optimal for wear coatings. Thin
films
Thin Film Properties
• Corrosion resistant
• Scratch resistant
• Increased Hardness
• Low friction
Uses
• Tool industry
• Automotive industry
3. Thornton, J.A.
3. Thornton, J.A.
3. Thornton, J.A.
1. Hoffman, D. W., & McCune, R. C. (n.d.). Microstructural Control of Plasma-Sputtered
Refractory Coatings. Handbook of Plasma Processing Technology, 483-517. Retrieved from
http://www.atechsystem.co.kr/sub1/pdf/115.pdf
2. Hoffman, D. W., & McCune, R. C.