Conference based on the research developed during my 2013-2014 postdoc at Institut des Matériaux Jean Rouxel (Nantes, France)

1. Kinetic growth of binary
compounds by reactive
sputtering magnetron
Dr. Javier García Molleja
Director: Dr. Pierre-Yves Jouan

2. Biography
 Grade
 PhD
 PostDoc #1
 PostDoc #2

3. Grade in Physics (2001-2006)
 Developed at: Universidad de Córdoba
(Córdoba, Spain).
 Main topics studied:
Plasma Physics
Simulation and structure of processors

4. PhD (2007-2012)
 Developed at: Plasma Physics Group, Instituto de Física de Rosario –
Universidad Nacional de Rosario (Rosario, Santa Fe, Argentina).
 Group staff:
 Principal: Dr. Jorge N. Feugeas
 Researcher: Dr. Bernardo J.A. Gómez
 PhD researchers: Lic. Leonardo Rico, Lic. Javier García Molleja, Lic. Lucio M.
Isola, Lic. Juan M. Bürgi, Lic. Maia M. López
 Other members: Téc. Javier M. Cruceño, Bach. Antonela Comisso
 Director: Jorge Néstor Feugeas
 Advisor: María Dolores Calzada Canalejo
 Thesis title: Characterization of expanded austenite generated by ion
carburization in stainless steels. Study of stability on light energetic ion
beam irradiation.
 Thesis jury: María M. Milanese, Roberto R. Koropecki, Oscar A. de Sanctis.

5. PhD (2007-2012)
 Fellowships: Universidad de Córdoba (2006, contract) ANPCyT (2006, 2009), ACIFIR
Foundation (2009), Conicet (2010).
 Formation works:
 Multilayers and superlattices generated by PACVD
 Study of AlN monolayer and AlN/TiN multilayer deposition by magnetron sputtering
 Study of metallographic techniques and microhardness tests for thin film characterization
 Languages:
 English
 French
 Subjects:
 Spectroscopy of surfaces
 Introduction to plasma physics
 X-ray crystallography
 Atomic force microscopy
 Experimental techniques on plasma physics
 Introduction to ceramic materials
 Optical plasma diagnosis

6. PhD (2007-2012)
 Carburization: surface modification with carbon atoms
using a cold, low pressure plasma.
 In austenitic steels (fcc structure) carbon atoms distort
the crystal and form the so called expanded austenite.
 Mechanical properties, like wear resistance, hardness…
are improved.
 Thesis motivation: searching of experimental conditions
in order to obtain excellent performance of AISI 316L
stainless steels; understanding of expansion
mechanisms; stability under ion irradiation.

7. PhD (2007-2012)
 Expanded austenite obtained at 30 min vs. 4 hours in
bibliography.
 90 % of total expansion obtained in this time.
 High current density provokes these effects but enhances
pitting corrosion.
 Carbon are lodged as bonded in the first stages and in
bulk, but the rest of carbon are presented as free in
surface.
 Graphitic carbon enhances wear resistance.
 The process develops stacking faults.

8. PhD (2007-2012)
 Atom diffusion is activated after a temperature threshold,
time is not relevant.
 AlN acts as protective barrier against oxidation.
 Deuterium or helium irradiation develops lattice parameter
shrinking.
 A peak fixed at 43.3° is always present.
 Ion bombardment provokes atom diffusion and melting.
 Recrystallization is discovered. Nanograins are responsible
of this peak located at 43.3°.

9. PostDoc (2012-2013)
 Developed at: Plasma Physics Group, Instituto de Física de Rosario –
Universidad Nacional de Rosario (Rosario, Santa Fe, Argentina).
 Group staff:
 Principal: Dr. Jorge N. Feugeas
 Researcher: Dr. Bernardo J.A. Gómez
 PostDoc researchers: Dr. Javier García Molleja
 PhD researchers: Lic. Juan M. Bürgi, Lic. Maia M. López, Lic. Antonela Comisso
 Other members: Téc. Javier M. Cruceño
 Director: Jorge Néstor Feugeas
 Co-Director: Raúl Eduardo Bolmaro
 Work title: Development of mosaic target for TiAlN ternary compound
deposition by reactive magnetron sputtering.
 Fellowship: ANPCyT (2012).

10. PostDoc (2012-2013)
 Work motivation:
 Development of mosaic targets
 AlN and TiN compounds deposition with magnetron
sputtering
 Cutting blades of tungsten carbide coated with TiAlN,
analysis of the mechanical properties
 Study of AlN kinetic growth using synchrotron light
 Work developed under collaboration with a
private timber enterprise.

11. PostDoc (2012-2013)
AlN deposition with magnetron sputtering.
New reactor made in order to study in-situ the
film growth process with synchrotron light.
Some conditions inhibit (00·2) plane formation.
So, it is possible to tailor thin films with
changing properties.

12. New PostDoc (2013-2014)
 Developed at: Laboratoire des Plasmas et des Couches
Minces, Institut des Matériaux Jean Rouxel (Nantes,
Loire-Atlantique, France).
 Team coordinator: Dr. Pierre-Yves Tessier
 Section involved: Couches Minces Homogènes
 Director: Pierre-Yves Jouan
 Work title: Growth kinetics of III-V film compounds
deposited by reactive magnetron sputtering.
 Fellowship: CNRS.

13. Research developed
 Theoretical background:
HiPIMS principles
The role of metastable argon
 Experimental analyses:
CrN kinetic growth under different parameters
NiO film characterization and properties

14. HiPIMS concepts
 Typical magnetron sputtering technique is based mainly
in the ejection of neutral atoms from the target.
 Ions are preferred instead of neutrals: many reaction
capabilities and redirection using electric fields.
 In order to obtain a high amount of ions, power density
must yield in the kW·cm-2
range.
 Target melting is avoided with a pulse source and high
voltage given to the plasma.
 These are the principles in which HiPIMS technique is
based.
 Unbalanced magnetrons confine ions and they can direct
the plasma to the substrate.

15. HiPIMS concepts
 Power source has a lot of
importance.
 Time delaying in plasma ignition
and discharge DC-like plateau are
matters of fact.
 It was observed lower deposition
rate than in DC sputtering
because of selfsputtering effects.
 If the power is very high, important
sideways ion deflection can be
observed.
 With HiPIMS sputtering technique,
sidewall deposition and denser
films can be obtained.
 It is detected a phenomenon
called sputter wind based on the
collision between target particles
with plasma gas; rarefaction
process is triggered.
G. Greczynski et al. (2010)
J.T. Gudmundsson et al. (2012)
D. Lundin (2010)

16. HiPIMS concepts
 Mass spectrometry is a useful tool.
 Time and energy integrated spectra
give important results.
 In time-integrated spectra it is
possible to see a high population of
ions and double ionized particles,
too.
 Energy tails are longer than in DC
sputtering.
 Each distribution has two peaks:
 One at high energies, originated
from the sputtered particles
(Sigmund-Thompson distribution).
 Other corresponding at low energies
from collision processes (Maxwell-
Boltzmann distribution) with
maximum imposed by the floating
potential.
 In some cases, a third peak appears
due to shockwave processes with
the reactor walls.
P.-Y. Jouan et al. (2010)

17. HiPIMS concepts
 In energy-integrated spectra, it is possible
to see the arrival of each species.
 Faster target ions, backscattered ions and
Ar ions are the first ones.
 After that, reactive gases reach the
measurement window.
 Finally, slow ions after thermalizing
processes, are detected, mainly gas
atoms.
 Maxima of doubly ionized ions are detected
during the rising slope of singly ionized
ions.
 After pulse off, ionic species still are
detected.
P.-Y. Jouan et al. (2010)
G. Greczynski et al. (2010)

18. The role of metastable Ar in
HiPIMS
 Metastable Ar can play as energy reservoir during HiPIMS
discharges.
 It is important to see which mechanisms promotes Arm
formation and
Arm
destruction.
 3
P2 and 3
P0 are the most relevant metastables states in argon atoms.
 Velocity profiles or Arm
are bimodal, so shock wave effects and
disturbances are the main responsible of this.
 Generally, this means a loss of Arm
, thermalizing collisions and wall-
plasma interaction destroy the anisotropic Arm
population.
Y. Ohta et al. (2002)

19. The role of metastable Ar in
HiPIMS
 Indeed, there are two peaks in
the number density profile of Arm
:
near the cathode and in the
sheath-plasma boundary.
 Some authors point that both are
created by local production and
loss processes (electron impact
excitation), not by atom diffusion.
 Others authors point that is the
same peak, but shifted in the
afterglow temporal regime.
 At low energies, a peak splitting
can be seen: one remaining at
the same place and other moving
away the cathode.
A. Bogaerts et al. (2000)
G. Lotito et al. (2011)
G. Lotito et al. (2011)

20. The role of metastable Ar in
HiPIMS
 There are several excitation processes that provoke the creation of
Arm
and its destruction.
 Direct electron impact excitation from the ground state and stepwise
excitation from lower excited levels are the most important
production processes, as well as radiative decay and electron
impact de-excitation from higher levels.
 Fast atom-ion impact is another relevant mechanism.
 Electron impact excitation to higher levels and de-excitation to lower
levels are very important loss processes, together with radiative
decay to lower levels.
 These high energy levels starting from the 4d and 6s levels, are
primarily depopulated by Hornbeck-Molnar associative ionization.

21. The role of metastable Ar in
HiPIMS
 During the afterglow, the bulk of both the 3
P2 and 3
P0 metastable
states are formed 4-7 mm further from the cathode surface than
during the plateau.
 Argon ion-electron recombination followed by radiative relaxation is
the most probable mechanism of populating these levels.
G.P. Jackson et al. (2001)
G.P. Jackson et al. (2001)

22. The role of metastable Ar in
HiPIMS
 The area of optimal overlap between the plasma plume and the discharge is
about 6 mm away from the cathode, if ion production through Penning
ionization should be favored.
 At the same time the power density in the pulsed discharge should be
maintained relatively high.
 Although Penning ionization certainly plays an important role in the
generation of analyte ions throughout the discharge pulse, and particular
during the afterglow when direct electron impact ionization becomes less
likely due to a decrease of the electron density, it cannot explain the
manifold increase of the analyte ion signal observed by MS during the
afterglow.
 Possible role of Ar2 dimers and dimer ions in the formation of the afterglow.
G. Lotito et al. (2011) G. Lotito et al. (2011)

23. The role of metastable Ar in
HiPIMS
 It is important to see the effects of other gases than argon in the working atmosphere.
 With 1 % of N2 the excitation processes are changed.
 There is a transfer of energy from excited argon atoms to nitrogen molecules during
the voltage-on period, with a subsequent reduction in the number of metastable
states of argon.
 This reduction in metastable atoms reduces the ionization of sputtered atoms during
the voltage-on period, but does not significantly impact emissions from excited
analyte atoms because the latter are created mostly via collisions with electrons.
 In the afterglow, argon ion recombination leads to an increase in metastable states by
Penning ionization.
G.P. Jackson et al. (2003)

24. The role of metastable Ar in
HiPIMS
 When nitrogen is added it prevents electrons from collisionally cooling in the
afterpeak due to superelastic collisions with vibrationally excited states of N2,
formed during the voltage-on period.
 These superelastic collisions delay the onset of recombination because fast
electrons recombine less-readily than slow electrons, so ions and electrons
are lost by diffusion to the walls.
G.P. Jackson et al. (2003)
G.P. Jackson et al. (2003)

25. Chromium nitride thin films
 High thermal stability.
 High corrosion resistance.
 Mirror-like finish.
 Possible replacement of TiN in functional
components.

26. Chromium nitride thin films
 Hysteresis loop has
the typical shape, but
the curve is not well
closed.
 Hysteresis starts at
11 % N2 and finish at
36 % N2.
Histéresis (I=0.180 A, p=10.10 mTorr)
310
320
330
340
350
360
370
380
390
0 5 10 15 20 25 30 35 40 45
Nitrógeno (%)
Tensión(V)
Ida
Vuelta

27. Chromium nitride thin films
 Cr-N phase diagram shows
that over 50.0 % of nitrogen
content only CrN phase is
present. With low content of
nitrogen Cr is obtained and
Cr2N when percentage is 30.3
%.
 Deposition under 200 °C
inhibits phase mixture due to
different values of enthalpy of
formation. G. Bertrand et al. (1997)

28. Chromium nitride thin films
 Total flux: 10.0 sccm.
 Atmosphere:
 a) 100 % Ar,
 b) 80 % Ar + 20 % N2,
 c) 70 % Ar + 30 % N2, and
 d) 25 % Ar + 75 % N2.
 Time deposition: 10 min.
 Working pressure: 5 mTorr and 10 mTorr.
 Target-substrate distance: 3 and 5 cm.
 Target surface: 20.27 cm².
 DC power employed:
 High power process: 110.00-201.76 W (i.e. 6-9 W/cm²)
 Low power process: 38.21-61.00 W (i.e. 2-3 W/cm²)

29. Chromium nitride thin films
D.T. Nguyen (2013)

30. Chromium nitride thin films (5 cm)
 Adding nitrogen means lower deposition
rate (due to target poisoning).
 At high power we can observe two
different behaviors:
 Cr and CrN30: higher pressure, higher
thickness.
 CrN20 and CrN75: higher pressure, lower
thickness.
 At low power, higher thicknesses are
reached at 10 mTorr (high number of
particles). CrN75 samples have the
opposite behavior. However, it’s only
4.32 nm of difference. Perhaps at this
condition deposition rate it’s the same
(complete poisoning at these molecular
nitrogen content).
 In general, high energy particles avoids
quick growth, so at lower pressures good
thicknesses are obtained.

31. Chromium nitride thin films (5 cm)
 At low power CrN (111)
plane is always detected.
Its intensity lowers with the
percentage of nitrogen.
 At high power peaks are
weak and Cr structure is
detected.
 Severe bombardment
inhibits CrN formation. It is
observed in samples at 20
% of N2.
 At high working pressures
peaks are more definite.

32. Chromium nitride thin films (3 cm)
 Adding nitrogen reduces growth rate
(poisoning).
 At high power there is always higher
thicknesses than at low power.
 At high power high pressure means
lower thickness.
 At low power there are two behaviors:
 Cr and CrN30: higher pressure, higher
thickness.
 CrN20 and CrN75: higher pressure,
lower thickness.
 More pressure means more collisions
and particle scattering but in principle is
some confusing to understand these
different behaviors.

33. Chromium nitride thin films (3 cm)
 For high power analysis is hard to obtain CrN phase,
possibly severe surface resputtering.
 With 75 % of N2 the Cr2N phase is really obtained?
 At higher pressure peaks are very weak.
 CrN compound is absent in CrN20-10-3-10 and CrN20-
10-3-10 samples, but is present in the other two
samples.

34. Chromium nitride thin films (3 cm)
 At low power peaks are well shaped.
 CrN (111) is present in CrN20 and CrN30 samples.
 Cr2N (200) is presumably present in CrN75 sample.
 At higher pressures peaks are more intense, maybe due
to high particle content.
 Crystal structure is conserved at low power.
 But it is important to know if there is a Cr2N when 75 % of
molecular nitrogen is used because phase diagram
forbids this.

35. Chromium nitride thin films
 Measuring the difference between the Si(400) theoretical and experimental (after
background subtraction and signal smoothing) positions, other peaks can be offset,
avoiding systematic errors of the diffraction equipment.
 Many peaks were discarded as having the Cr2N phase. Only three peaks remains as
suspects: CrN75-5-5-10 HP, CrN75-5-3-10 HP, and CrN75-5-3-10.
 Lattice parameter increases if the structure is stressed.
 Non-stoichiometric films deposited by sputtering has behaviors out of the phase
diagram predictions (morphological changes).

36. Chromium nitride thin films
 A bibliographical search gives that:
 Stresses provoke a CrN (111) peak shifting.
 A low deposition rate promotes CrN phase.
 When molecular nitrogen atmosphere is over 70 % CrN phase is present, but diffraction
peaks are severely shifted.

37. Chromium nitride thin films
 EDS analyses (15 kV) confirm the
elemental composition of these thin
films.
 According to the literature, and
observing again all the diffractograms
we can conclude that when 75 % of
molecular nitrogen is used in the
atmosphere, only the CrN phase is
achieved.
 But there is a high over-stoichiometry
(N-rich), so high lattice expansion is
detected.
 Similarly, film thicknesses may induce
compressive stresses also (when a
particular thickness is reached), so the
peak position is located at lower
angular values, creating confusion.
Sample Cr (at.%) N (at.%)
CrN75-5-5-10HP 39.6 60.4
CrN75-5-5-10 33.1 66.9
CrN75-10-5-10HP 38.4 61.6
CrN75-10-5-10 33.9 66.1
CrN75-5-3-10HP 42.7 57.3
CrN75-5-3-10 35.8 64.2
CrN75-10-3-10HP 41.9 58.1
CrN75-10-3-10 36.3 63.7

38. Chromium nitride thin films
 XPS results show different surface
elemental concentration with regard to
the film bulk.
 Carbon and oxygen are in high amount
in surface.
 In the bulk, chromium and nitrogen
prevail.
 Films deposited with high power have a
low quantity of contaminants in bulk (4
% vs. 11 %), and low carbon
concentration in surface than the
concentration in low power condition (45
% vs. 57 %).
 Cr elemental composition is higher than
the N one, because preferential
sputtering.
 At high power condition elemental
composition of Cr (54 %) and N (38 %)
are higher than in the low power
condition (49 % of Cr and 28 % of N).
 Some Cr3C2 formation is possible.
Surface: Cr 2p
Bulk: Cr 2p

39. Chromium nitride thin films
 Samples with identical
experimental parameters and
different nitrogen content show
a gradual decrease in CrN
(111) peak position.
 Lower growth rate possibly is
involved in this behavior.
Samples deposited at 3 cm
of target-substrate distance
have peaks at lower angular
values than films deposited
with a distance of 5 cm.

40. Chromium nitride thin films
 We have observed that at lower
pressures (5 mTorr) diffraction peaks
are located at lower angular values.
 In the beginning, with 20 % of N2
content, both peaks are located at the
same place but addition of nitrogen
provokes higher separation between
them.
When nitrogen percentage is
20 % or 30 % high power
provokes higher diffraction
angles than the ones obtained at
low power, but when N2 content
is 75 % this trend is reversed.

41. Nickel oxide thin films
 NiO is a p-type conductor compound.
 Probably has a rombohedral structure, but their lattice spacings are close to
a fcc one.
 Research in the field of photovoltaic cells and gas sensors.
 Studied as a Mott-Hubbard insulator. Interest in the field of transistors.
 There is some interest in batteries, too.
 In magnetron sputtering, cathode voltage has a characteristic shape divided
in five regions.
A. Karpinski (2011)

42. Nickel oxide thin films
 Different gas mixtures used:
 Ni: 100% Ar – 0% O2
 NiO7: 87,72% Ar – 12.28% O2
 NiO9: 84,75% Ar – 15.25% O2
 NiO13: 79,37% Ar – 20.63% O2
 NiO19: 72,46% Ar – 27.54% O2
 Depositions at 3 cm of target-substrate distance, at 5 mTorr of working
pressure, DC power supply and 100 W of power and 0.1 µTorr of base
pressure.
 Target cleaning of 5 min with Ar plasma. Target poisoning during 5-10 min.
 Substrates used: Si (100) and glass.
 Different thicknesses used: 10, 50, 100, 300, 500, and 1000 nm.
 Different times used: 5, 10 and 20 min.
 Different DC bias used: 0, 50, 100, 200, 300, 400, and 500 V.

43. Nickel oxide thin films
 Sigmund-Thompson distribution when Ar+
collides with Ni target.
 If Ar+
has energy between 400-450 eV:
 Sputtering yield is 1.62-1.74 at/ion,
 Mean energy of sputtered Ni is 19.81-20.63 eV/at (SRIM calculation) or
23.73-24.61 eV/at (theoretical values; using heat of sublimation gives
26.89-27.95 eV/at),
 Ar backscattered is 5.64-5.78% of total impinging particles.
 Ni0
in 97% Ar – 3% Ar+
gas at 5 mTorr and 150 °C has a λ=3.57 cm.
 Ni0
in Ar-O2 gas depends on molecular oxygen percentage. It is
assumed that ionization coefficient is very low and in each
discharge we have 80% O – 20% O2 of reactive gas.
 NiO7: λ=3.509 cm.
 NiO9: λ=3.474 cm.
 NiO13: λ=3.411 cm.
 NiO19: λ=3.333 cm.
 There are no collisions during the trip.

44. Nickel oxide thin films
 Our NiO films, under such a high oxygen
concentration in the atmosphere has an oxygen
excess.
 This process creates vacancies and electrical
holes, so NiO is a p-type conductor.
 Electrical holes are delocalized (band structure
is over the whole lattice), so Ni3+
localization is
not definite a priori.
 Two mechanisms are calculated, i.e.,
substitutional process and interstitial process:

45. Nickel oxide thin films (thickness)
NiO7
NiO9

46. Nickel oxide thin films (thickness)
NiO19
NiO13

47. Nickel oxide thin films (thickness)
 Generally, crystal structure is present in films 100 nm thick.
 NiO (111) plane is the most intense one, but as films growths, film is
textured in NiO (200) plane.
 Different regimes of discharge:
 Metallic regime: NiO7
 Transition regime: NiO9
 Poisoned regime: NiO13, NiO19
 (111) and (200) planes are prominent in poisoned conditions.
 (200) reduces surface energy
 (111) has a lot of adsorption sites, lower energy
 In NiO7 other planes prevail.
 In NiO9 (222) planes appears.
 Oxygen augmentation provokes (200) increase.

48. Nickel oxide thin films (thickness)
Thickness
(nm)
NiO7 (Å) NiO9 (Å) NiO13 (Å) NiO19 (Å)
10 - - - -
50 - - - 4.2342
100 - 4.2354 4.1176 4.2342
300 4.1972 4.2103 4.1861 4.1806
500 4.1855 4.1947 4.2285 4.2157
1000 4.1579 4.1932 4.2336 4.2131
Lattice parameters (tabulated NiO: 4.194 Å)

49. Nickel oxide thin films (thickness)
 There is a kind of competition between the corrected plane intensities,
principally (111) and (200) planes are involved.
 The other planes growing have the competition between themselves.
 (200) texture is stronger when thickness is over 1 µm.
 In NiO7 (coated in the metallic mode of sputtering) has different texture than
(111) and (200) ones.
 In the transition, NiO9, has a (222) strong plane, not the (111) one.
 In poisoned mode both planes are relevant.

50. Nickel oxide thin films (thickness)
 Thickness provokes stress relief: the film is free
to arrange their atoms without substrate
constraints.
 NiO7 started as stress-free but after this point
this sample had tensile stresses.
 NiO13 started with tensile stress, but quickly
there is a stress change behavior.

51. Nickel oxide thin films (bias)
NiO7
NiO9

52. Nickel oxide thin films (bias)
NiO19
NiO13

53. Nickel oxide thin films (bias)
 Area calculated by fitting with a Voigt function (ideal in X-
ray analyses).
 Different regimes of discharge:
 Metallic regime: NiO7
 Transition regime: NiO9
 Poisoned regime: NiO13, NiO19
 (111) and (200) planes are prominent in poisoned
conditions.
 In NiO7 other planes prevail.
 Oxygen augmentation provokes (200) increase.

54. Nickel oxide thin films (bias)
 Target regime is fundamental to decide the preferential orientation
obtained.
 Under severe bias, NiO7 has (220) and (311) planes highly
enhanced.
 Bias promotes (200) planes in the poisoned sputtering.
 During transition, i.e. NiO9 sample, (111) is enhanced with bias.

55. Nickel oxide thin films (bias)
 NiO7 is tensile. NiO13 changes with bias (from
compressive to tensile).
 It was not observed a strong change in stress with bias.
 Particle bombardment release stresses, but ion impact
degrades the surface smoothness.

56. NiO: resistivity
 Changing the oxygen percentage and the target-distance substrate
have effects in the resistivity.
 More oxygen content, more oxygen excess in the film and the
production the holes increases, so resistivity lowers.
 At 9 cm resistivity is higher than at 7 cm of target-substrate distance,
perhaps there is a crystalline failure under these conditions.
 But in NiO19 resistivity is similar.
ρ Units
NiO9-9cm 721 kΩ cm
NiO13-9cm 10.1 kΩ cm
NiO19-9cm 3.7 Ω cm
ρ Units
NiO9-7cm 12.8 kΩ cm
NiO13-7cm 4.9 kΩ cm
NiO19-7cm 11.2 Ω cm

57. NiO: resistivity
 NiO9 is obtained with a
target-substrate
distance of 3 cm.
 Bias increase develops
a severe resistivity
decrease.
 This effect is related to
the ion bombardment.
 Comparing with
reported data, these
films could act like a
Mott-Hubbard insulator.
ρ Units
NiO9-100V 12.5 MΩ cm
NiO9-300V 380 Ω cm
NiO9-400V 1.08 kΩ cm
NiO9-500V 82 Ω cm

58. NiO: resistivity
 Electrical resistivity in NiO9, NiO13 and NiO19 samples with different thicknesses has
been measured.
 Resistivity grows with thickness.
 It is important avoid peeling effects.
 Crystalline ordering can play a key factor in the location of defects, electrical holes
and vacancies.

59. NiO: resistivity
 Oxygen insertion provokes a non-stoichiometric NiO, with excess in oxygen.
 High amount of nickel vacancies and electrical holes improve the carrier
mobility.
 In NiO19, the thickness factor is almost irrelevant.
 In NiO pure the resistivity is 180 TΩ·cm. All films analyzed had lower values.

60. NiO: resistivity
 Resistivity measured in
temperature gives the activation
energy.
 It is observed two phenomena: one
at high temperatures and other at
low temperatures (200-50 K).
 This point of change is imposed by
our experimental conditions.
 In NiO9-300V film, the activation
energy in the high temperature
range is 0.22 eV.
 In NiO13-50nm sample, activation
energy at high temperatures is 0.20
eV.
 In NiO19-50nm sample, activation
energy at high temperatures is 0.16
eV.
 Remember that EB=3.8 eV in NiO
pure.
 Fermi level is shifted by
intermediate states between the
valence and conduction bands.

61. Summary
 HiPIMS is a promising technique in order to deposit denser films, but it will be
necessary more plasma characterizations to understand some behaviors.
 Metastable argon can be considered in order to maintain ion production in the
afterglow regime.
 CrN films obtained at high power condition presented poor crystalline behavior and
this effect is relevant when target-substrate distance is 3 cm.
 On the other hand, films obtained at high power reduced their bulk and surface
contaminants. All films were N-rich.
 A high nitrogen percentage provoked compressive stresses, the same effect with more
working pressure, low target-substrate distance and high power.
 NiO films have a hole-production mechanism when they are O-rich. Films with high
thickness showed that (200) and (111) planes were prevailed under high amount of
O2.
 Poisoned mode promoted (200) plane and metallic mode promoted (220), (311) and (222)
planes. Residual stresses were decreased with thickness.
 Under bias conditions, residual stress is lowered under 200-300 V bias. In poisoned mode
high bias promoted (200) plane and in metallic mode (220) and (311) planes are enhanced.
 Sample resistivity is lowered by substrate bias. High amount of oxygen in the atmosphere
promoted resistivity reduction, but increasing target-substrate distance had not improvement
in this value.

62. First Nantes-Rosario collaboration
 Interfacial oxygen imposes compressive
stresses.
 Far away from this zone AlN grows in
columnar fashion, relieving stresses and
inducing tensile strains.
 Internal O does not play any relevant role.

63. Future work with IMN involved
 Development of Nantes-Rosario collaboration with two new papers:
 Effect of pressure on morphology and residual stress in AlN thin films (to
present in Argentinean congress as hot topic in the country).
 Changes on texture in AlN films analyzed in-situ by synchrotron radiation
(publication of our results obtained in Campinas, Brazil).
 Export the HiPIMS technique to Rosario in order to develop metamaterials.
 Elaboration of some papers in which IMN affiliation is present:
 Production and characterization of AlN coatings deposited by PVD magnetron
sputtering: study of influence of nitrogen gas concentration and substrate bias
voltages (submitted manuscript).
 Behaviour of nitrided and carburised AISI 316L and AISI 904L stainless steels
under severe light ion beam irradiation by plasma focus (continuing some PhD
thesis results).
 AlN protective thin films in order to avoid wear and corrosion processes in
aluminum alloys (results obtained in collaboration with researchers from
Lille).
 Write papers about the present results, especially with NiO compound.

64. Things to do
 Improve some graphics and measurements.
 Development of resistivity measures in temperature.
 Theoretical comprehension about Mott-Hubbard
insulators.
 Write a report to share with PCM laboratory, especially
with Dr. Jouan in order to do a database of my PostDoc
at IMN.
 Possibility to visit Nantes one or twice times per year
during a few weeks to continue with our results and
active collaboration.
 Search a permanent job!

65. Now, come back to Rosario, where
the Flag Monument is placed
 But I’ll go,
perhaps, with
this flag…