Nos tutelles

CNRS UPS Enseeiht

Rechercher



Groupes de recherche


Accueil > Groupes de Recherche > Matériaux et Procédés Plasma > Thèmes de recherche

Plasma and materials

par Agnès Gaunie Picart - publié le


This topic can be separated into three parts :


Homogeneous thin films.

In this sub-topic, thin film deposition processes from organosilicon, silane or hydrocarbon precursors are studied. We have shown particularly the possibility to elaborate materials of different densities with a same precursor with different kinds of discharges (Microwave MMP – DECR, Surfatron or Atm. Pressure Townsend discharge APTD). For instance, very porous materials are obtain from organosilicon post discharge (surfatron) compared to those more dense obtain from DC discharge or APTD.

Moreover, Low pressure or atmospheric pressure discharges allow us to deposit thin film from organic to inorganic composition. The composition of the coating is mainly managed by the gas mixture : N2O/HMDSO diluted in N2 for APTD and HMDSO/O2 in low pressure plasma (DECR, RF ...). Thus, multilayer coatings (organic / inorganic stacks) with very low stress have been deposited on polymer films to improve their barrier properties : This kind of stack on PET sheet, leads to very low water vapour permeation value and can be useful for the encapsulation of Lithium microbatteries.

SiOx coating on Si substrate from N2O/HMDSO (diluted in N2) APTD. Color changes are due to thickness variation of the coating as, progressively the precursor is consume (along the gas flow : from left to right).

[retour]


Thin films on « complex » substrates.

This topic is a new challenge in the field of plasma processes. Conformal layers on microstructured polymer substrates are studied in the framework of Pixcell – Lab and based on comparison between Low and high pressure processes. At low pressure we have shown the shadow effect and ions play the main roles on the shape of the deposited layers, whereas at atmospheric pressure, the deposition process is mainly controlled by the diffusion of neutral radical species. These studies led to a transfer of technology (Low pressure pilot line reactor).

Conformity of a coating obtains from an HMDSO Microwave MMP – DECR discharge on a microstuctured substrate (6 µm height) – Top and bottom part of the structure).

Simulated growth rate profile (kg/m2.s) in a 15µm×15µm trench in atmospheric pressure discharge conditions. The species doesn’t reach the bottom of the trench due to their very low diffusion rate. Results from 3D - reactive transport modelling.

[retour]


Nanostructured thin films and / or nanoparticles containing materials.

In recent years our work has clearly turned towards the plasma deposition of nanostructured layers and / or nanoparticles containing materials that give peculiar properties. Indeed, under certain plasma conditions, clusters created in the plasma phase can be co-deposited with a homogeneous matrix to produce nanocluster-containing materials.

Silicon nano crystal in SiOxNy layer deposited in SiH4-N2O RF discharge pulsed by square signal.

For instance, we’ve studied the deposition of Carbon-Carbon nanocomposite thin films (graphitic clusters imbedded in a hydrocarbon matrix) in a C2H2 Multipolar Microwave Plasma excited by DECR. These materials reveal specific (peculiar) behaviours (photo induced relaxation - (collaboration with MDCE)) and would be useful in the field of photovoltaic applications. Moreover, the nanostructuration of the layer make possible the coating of the Stents (medical applications).

SEM picture of a carbon – Carbon nanocomposite layer from a C2H2 MMP – DECR Plasma. Dust average diameter : 200 nm (independent of the process parameters). Dust composition : Carbon (metal free) or metal/carbon mixture.

Moreover, in the case of SiH4–N2O mixtures, RF plasma can insert nanoscale Si clusters in SiOxNy matrix. The silicon amount is adjusted by the ratio of flow rate SiH4–N2O and by the RF power modulation by a square pulse with variable width. The tunneling injection and storage of electrical charges on silicon nanocrystal have been demonstrated on very thin film stack by electrical measurements (C(V)) thus giving these materials potential in the field of nonvolatile memories.
Besides, in the case of processes involving the silver sputtering and plasma polymerization in HMDSO/Ar mixtures, the Ag particle amount in the layer is modulated by pulsed injection of reactive gas. Biocide properties of such materials have been identified.

TEM planar view of nanosilver-containing SiOxCyH matrix.

[retour]


References :

Thesis :

  • Messaoud Bedjaoui (2006) « Elaboration de dispositifs MOS contenant des nanocristaux de Si obtenus par PECVD pulsé »
  • David Escaich (2006) « Caractérisation et élaboration de couches de carbones amorphes hydrogénés à propriétés optiques par procédés plasmas »
  • Ionut Enache (2007) « Etude expérimentale et modélisation du transfert de matière et des instabilités dans les décharges de Townsend à pression Atmosphérique en mélange HMDSO-N2O–N2 et SiH4–N2O–N2 »
  • Isabelle Savin de Larclause (2008), « Dépôt organosilicié par plasma froid basse pression et pression atmosphérique sur substrats microstructurés »
  • Maria Calafat Ramirez (2008), « Formation de poudres dans des décharges d’acétylène dans un réacteur PMM- RCER : Etudes des nanocomposites carbone-carbone et de leurs applications »

Main publications :

  • A. Bellel, S. Sahli, P. Raynaud, Y. Segui, Z. Ziari, D. Escaich, G. Dennler ; Improvement of the polyimide surface wettability using SiOx films deposited in a DECR reactor from HMDSO/O2 mixtures ; Plasma Processes and polymers, Volume 2, p. 586, 2005
  • R. Clergereaux, D. Escaich, S. Martin, F. Gaillard, P. Raynaud ; Ageing of plasma deposited carbon layers : thickness and material structure effect ; Thin Solid Films, Volume 482, p. 216, 2005
  • P. Raynaud, B. Despax, Y. Segui, H. Caquineau ; Fourier transform infrared plasma phase analysis of hexamethyldisiloxane discharge in- microwave multipolar plasma at different electrical powers ; Plasma Processes and Polymers, Volume 2, pp. 45-52, 2005
  • F. Massines, N. Gherardi, A. Fornelli, S. Martin ; Atmospheric pressure plasma deposition of thin films by Townsend dielectric barrier discharge ; Surface Coating Technology, vol 200, pp. 1855-1861, 2005
  • M. Bedjaoui, B. Despax, M. Caumont and C. Bonafos ; Post-annealed silicon nanocrystal formation on substoichiometric SiOxNy (x < 2, y < 1) layers deposited in SiH4-N2O radiofreaquency discharges ; Eur. Phys. J. Appl. Phys. 34 147-150 (2006)
  • A. Bellel, S. Sahli, Z. Ziari, P. Raynaud, Y. Segui, D. Escaich ; Wettability of polypropylene films coated with SiOx plasma deposited layers ; Surface and coating technology 201, 129–135, 2006
  • Clergereaux R., Escaich D., Savin de Larclause I., Bernecker B., Raynaud P. ; Plasma deposition of carbon layer : correlations between plasma parameters, film structure and optical properties ; Diamond and Related Materials 15, 888 (2006)
  • P. Supiot, C. Vivien, A. Granier, A. Bousquet, A. Mackova, D. Escaich, R. Clergereaux, P. Raynaud, Z. Stryhal, J. Pavlik ; Growth and modification of organosilicon films in PECVD and Remote Afterglow Reactors ; Plasma Processes and Polymers, 3, 100 (2006)
  • B.Despax, P. Raynaud ; Deposition of Polysiloxane thin films containing silver particles by an RF asymmetrical discharge ; Plasma Processes and Polymers, 2007, (4)2, 127-134
  • R. Clergereaux, M. Calafat-Ramirez, F. Benitez, D. Escaich, I. Savin de Larclause, P. Raynaud, J. Esteve ; Comparison between continuous and microwave oxygen plasma post-treatment on organosilicon plasma deposited layers : Effects on structure and properties ; Thin Solid Films, 2007, (515)7-8 , 3452-3460
  • H. Kihel, R. Clergereaux, D. Escaich, M. Calafat-Ramirez, P. Raynaud, S. Sahli, Y. Segui ; Investigations on electrical properties of a-C:H thin films deposited in a Microwave Multipolar Plasma reactor excited at Distributed Electron Cyclotron Resonance ; Diamond and Related Materials, 2008, (17)7-10, 1710-1715
  • Kihel M., Clergereaux R., Salhi S., Escaich D., Segui Y., Raynaud P. ; Characterization of a-C:H thin films deposited from C_2 H_4 by PECV Microwave discharge ; Materials Science Forum, Vol 609, pp. 49-52, 2009
  • Saulou C., Despax B., Raynaud P., Zanna S., Marcus P., Mercier-Bonin M. ; Plasma-engineered polymer thin films with embedded nanosilver for prevention of microbial adhesion ; Solid State Phenomena Vol 151, pp. 95-100, 2009
  • C. Sarra-Bournet, N. Gherardi, S. Turgeon, G. Laroche, F. Massines ; Deposition of Functional Hydrogenated Amorphous Carbon-Nitride film (a-CN:H) using C2H4/N2 Townsend Dielectric Barrier Discharge ; Eur. Phys. J. Appl. Phys. 47(2), 22820, (2009)

Contractual activities :
European project Napolyde, SIDUR, Cost-587, ANR Biopleasure, ANR Plasmasol, ANR Encapsat, PEPS - ST2I, AGC Flat Glass Europe, Essilor (Pixcell), Applied Materials

Internal collaborations :
PRHE, MDCE, LM

Scientific collaborations :
GDR Surgeco, GDR Arches, GDR Temps, LISBP, CPTP, LGC, CEMES, PROMES, GPFrem, IMN, Université de Laval (Canada), Unviersité de Bari (Italie), Université de Constantine (Algérie)

[retour]