Conference developed at Commission des Amériques (Université de Nantes). Year 2013.

1. Growth kinetics in transition-metal
ceramic compounds
Javier García Molleja
www.cnrs-imn.fr
Nous imaginons pour vous les matériaux de demain

2. Where am I?
Postdoctoral researcher at Institut des Matériaux
Jean Rouxel (February 2013-February 2014).
Director: Pierre-Yves Jouan
Institutions:
-Centre National de la Recherche Scientifique
-Université de Nantes
-Chemie
et
Interdisciplinarité:
Synthèse,
Analyse, Modelisation (CEISAM)
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3. Institutions
Graduate in Physics by Universidad de Córdoba (Spain, July
2001-July2006).
Expertise in plasma physics and numerical simulation.
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4. Institutions
PhD degree by Universidad Nacional de Rosario (Argentina,
June 2007-March 2012).
Surface treatment of steels using plasmas with carbon or
nitrogen. Characterization and irradiation with high energy
beams.
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5. Institutions
Postdoctoral researcher at Instituto de Física de Rosario
(Argentina, May 2012-February 2013).
Deposition of ternary compounds on cutting blades and
adhesion characterization.
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6. Workplace
Institut des Matériaux Jean Rouxel. Director: Guy Ouvrard.
It is an UMR institution (Centre National de la Recherce
Scientifique and Université de Nantes).
Six different research laboratories, including Plasma et
Couches Minces one. Director: Pierre-Yves Tessier.
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7. Workplace
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8. So, what is a plasma?
Almost the 90% of visible matter in the universe
is under plasma condition (including stars,
stardust, nebulae, lightnings and the most part of
our atmosphere!).
Historically, the plasma has been considered the
fourth state of the matter. Gases with high
energy (hot gases) may suffer ionization, so this
gas is composed by neutral particles, positive
ions and electrons.
If this system responds to electromagnetic fields,
it is called a plasma.
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9. So, what is a plasma?
We can use plasma for
many
things,
like
treatment of surfaces
without
using
high
temperatures.
To cover delicate things.
Cleaning procedures.
Lighting devices.
Commercial signals with
neon.
Or they are used as
space engines.
Yes, I include our new
plasma TVs.
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10. Magnetron… what?
Yes, magnetrons have magnets and we use them to work
easily (not always) with plasmas.
Magnetrons confines plasma electrons and provoke a lot of
ionizations.
These positive ions (argon ions, generally) are attracted to
the cathode, place where there is a target made of a
material of interest (aluminum, chromium, nickel…).
The material is sputtered and these particles travel until
they reach a substrate, thus they deposit on it.
If the plasma contains reactive gases (nitrogen, oxygen…),
not only noble ones, is probable a reaction, making a new
compound.
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11. Ok, a sketch of this magnetron sputtering
process
This
process
is
stable with different
power supplies.
We can play with
this.
Working pressure is
very low: less than
100000 times the
atmospheric
pressure.
We
need
special
pumps and avoid
the
entrance
of
contaminants.
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12. Chromium nitride
Film deposition is analyzed under different
nitrogen concentrations in our plasma, different
working pressure, and different magnetronsubstrate distance.
Let’s complicate a bit more this stuff: what
happens if the power of the discharge is
changed?
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13. Chromium nitride
Different working pressure is
relevant under high nitrogen
percentages.
This
huge
quantity
of
nitrogen provokes crystal
distortion.
Stresses
are
developed.
High
power
discharge
augments
the
chromium
percentage
and
reduces
oxygen
and
carbon
contamination.
Possible
new
surface
compounds.
It is demonstrated that
oxygen is only a surface
contaminant.
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14. Nickel oxide
In this case we only change oxygen percentage in
our plasma.
We are studying the growth kinetics, so it is
interesting to see how crystal structure is
changed with thickness.
And we ask ourselves if different bias (negative
voltage in the substrate to attract some ions) has
an important role or not.
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15. Nickel oxide
Yes, we have structural
evolution with thickness,
and with bias in some
extent.
Variation with thickness:
substrate imposes internal
stresses.
Variation with bias: ion
bombardment
changes
preferential
orientation
until
some
point
is
reached. After that, it shall
consume everything!
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16. Nickel oxide
There is an influence of
oxygen content, there is
a distortion of crystal
structure.
Indeed, at same bias or
at
same
thickness,
oxygen
promotes
or
avoids some orientations,
so we can distinguish two
discharge regimes.
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17. Nickel oxide
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18. Future projects
Synchrotron facility in Campinas (Brazil).
X-ray beam with high intensity and good properties.
Useful to measure in-situ thin film growth.
Understanding of nucleation processes, structural changes
with time.
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19. Future projects
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20. Future projects
Development of NiO (nickel oxide) with new
techniques, like HiPIMS.
Understanding of growth kinetics and residual
stresses.
Application to solar cells: photovoltaic devices.
Theoretical study and experimental development
of Mott-Hubbard insulators with NiO in order to
apply in the field of microelectronics.
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21. Personal project
Elaboration of papers related to NiO and CrN
compounds.
Improve the Nantes-Rosario relationship with
more collaboration:
-Aluminum nitride growth in Campinas
-Preliminary work with metamaterials
Find a new job, a permanent position (university,
R&D company) if it is possible.
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