M. Lejeune - Academia.edu (original) (raw)
Papers by M. Lejeune
Optics Communications
Abstract Hybrid one dimensional photonic crystal (1D PC) based on alternating layers of inorganic... more Abstract Hybrid one dimensional photonic crystal (1D PC) based on alternating layers of inorganic materials, the silicon (Si), grown by radiofrequency magnetron sputtering and organic compound, HMDSO mixed with nitrogen N 2 (HMDSO+N2), deposited by radiofrequency Plasma Enhanced Chemical Vapor Deposition (RF-PECVD) for different N 2 /HMDSO flow rate at a fixed power of 200W. As the refractive index of silicon (Si) is n=3.4, to obtain a good contrast index between the inorganic and organic layers leading to appearance of large photonic band gap, we have varied the flow of the mixed gaz (HMDSO+N2) for having a lower refractive index 1.7 corresponding to a layer with the same chemical composition element of the SiNOCH material as confirmed by IR measurement. After optimization of the Si and SiNOCH thickness layers with respect to the Bragg low, we have measured the photonic band gap (PBG) of Si/SiNOCH photonic structure through transmission and reflection spectra. The PBG appears after 5 periods of alternating layers with a width of 740 nm in the near infrared (NIR) region centered at 1500 nm. Our experimental results are interpreted successfully by a theoretical model based on the transfer matrix method (TMM).
Applied Surface Science
Abstract Electron-beam-induced deposition of various materials from suitable precursors has repre... more Abstract Electron-beam-induced deposition of various materials from suitable precursors has represented an established branch of nanotechnology for more than a decade. A specific alternative is carbon deposition on the basis of hydrocarbons as precursors that has been applied to grow various nanostructures including masks for subsequent technological steps. Our area of study was unintentional electron-beam-induced carbon deposition from spontaneously adsorbed hydrocarbon molecules. This process traditionally constitutes a challenge for scanning electron microscopy practice preventing one from performing any true surface studies outside an ultrahigh vacuum and without in-situ cleaning of samples, and also jeopardising other electron-optical devices such as electron beam lithographs. Here we show that when reducing the energy of irradiating electrons sufficiently, the e-beam-induced deposition can be converted to e-beam-induced release causing desorption of hydrocarbons and ultimate cleaning of surfaces in both an ultrahigh and a standard high vacuum. Using series of experiments with graphene samples, we demonstrate fundamental features of e-beam-induced desorption and present results of checks for possible radiation damage using Raman spectroscopy that led to optimisation of the electron energy for damage-free cleaning. The method of preventing carbon contamination described here paves the way for greatly enhanced surface sensitivity of imaging and substantially reduced demands on vacuum systems for nanotechnological applications.
Superlattices and Microstructures
Abstract Quasi-periodic one-dimensional Cantor photonic crystals are elaborated by depositing alt... more Abstract Quasi-periodic one-dimensional Cantor photonic crystals are elaborated by depositing alternating silicon and silica Si/SiO 2 layers by radiofrequency magnetron sputtering technique with cold plasma. Transmittance and reflectance spectra of these quasi crystals exhibit a large photonic band gap in the infrared range at normal incidence which is well reproduced by a theoretical model based on the transfer matrix method. The obtained wide photonic band gap reveals the existence of permitted modes depending on the nature and characteristics of the built in system which can constitute optical windows. This effect can be a good alternative for the design of flexible filters used in many areas of applications such as telecommunication and optoelectronic devices.
Solid State Communications, 2001
Analysis of carbon nitride ®lms (CN x) deposited by RF magnetron sputtering on crystalline silico... more Analysis of carbon nitride ®lms (CN x) deposited by RF magnetron sputtering on crystalline silicon, under different target selfbias, is reported. The properties of ®lms were determined in their as-deposited state using X-ray photoelectron spectroscopy (XPS), IR absorption, transmission spectroscopy and residual stress measurements. The presence of various types of C±N bonds, as well as of hydrogen and oxygen, is revealed. A good correlation is observed between the variation of N/C ratio, the optical gap E 04 and the internal stress as a function of the target bias. The optical gap E 04 decrease is discussed in terms of N/C ratio evolution, the sp 2 bond content and the local distortions of the sp 2 bonds.
Thin Solid Films, 2003
Analysis of carbon nitride films (CN) deposited by radio frequency (RF) magnetron sputtering on c... more Analysis of carbon nitride films (CN) deposited by radio frequency (RF) magnetron sputtering on crystalline silicon, under x different target self-bias, is reported. Plasma characterisation was performed using mass spectroscopy (MS) and the properties of films were determined in their as deposited state using elastic recoil detection analysis (ERDA), nuclear reaction analysis (NRA), X-ray photoelectron spectroscopy (XPS), infrared absorption, transmission spectroscopy and photothermal deflection spectroscopy (PDS) experiments. A good correlation is observed between the variation of NyC ratio and the growth rate. The resulting changes in the microstructure can be analyzed in terms of surface processes, nitrogen incorporation within the films and the Csp content. 2
Surface and Coatings Technology, 2002
ABSTRACT Analysis of carbon nitride films (CNx) deposited by RF magnetron sputtering on (100) sil... more ABSTRACT Analysis of carbon nitride films (CNx) deposited by RF magnetron sputtering on (100) silicon wafers, under different target self-bias, is reported. The properties of as-deposited films were determined using X-ray photoelectron spectroscopy (XPS), IR absorption, Raman spectra, transmission spectroscopy and photothermal deflexion spectroscopy (PDS). The presence of various types of CN bond, as well as of hydrogen and oxygen, was revealed. Good correlation was observed between the variation of nitrogen content (N/C ratio), the optical gap and the Raman features as a function of the target bias. The optical gap decrease is discussed in terms of N/C ratio evolution and the sp2 content.
The present work provides surface characterization for all steps involved in the fabrication of a... more The present work provides surface characterization for all steps involved in the fabrication of a direct label free piezoelectric immunoprobe, using techniques such as Ellipsometry, Atomic Force Microscopy, Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and X-Ray Photoelectron Spectroscopy (XPS). Active amino groups were successfully provided on the quartz crystal surface through plasma deposition of allylamine polymer film (ALL) [1] and were further utilised for antibody (Ab) immobilization. Results from this work show the possibility of producing simple, direct piezoelectric immunoprobes through appropriate antibody orientation without the need for labeled compounds. The combination of surface analytical, optical and mass balance techniques is confirming the effectiveness of these immunosensor fabrication strategies.
Solid State Phenomena, 2001
Vacuum, 2009
... 773782. Article | PDF (720 K) | View Record in Scopus | Cited By in Scopus (23). [3] Zaidi S... more ... 773782. Article | PDF (720 K) | View Record in Scopus | Cited By in Scopus (23). [3] Zaidi S, Lamarque F, Favergeon J, Carton O, Prelle C. Proc of Mecatronics, 2008, paper 143. [4] M. Boucinha, P. Brogueira, V. Chu and JP Conde, Appl Phys Lett 77 (No. 6) (2000), pp. ...
Thin Solid Films, 2004
ABSTRACT Nanocrystalline hydrogenated silicon films were grown by radiofrequency magnetron sputte... more ABSTRACT Nanocrystalline hydrogenated silicon films were grown by radiofrequency magnetron sputtering in an mixed Argon/Hydrogen (30%/70%) plasma. For some series Helium or Nitrogen was added to the gas mixture. The films were grown at 250 °C for total different pressures varying from 5 to 15 Pa. The crystalline fraction increases with pressure from 85 to 93% but at the same time the porosity of the films increases from 11 to 19%. This relatively high porosity leads to an important post-growth contamination of oxygen as revealed by IR absorption spectroscopy and nuclear reaction analysis (NRA) and can explain the low stress observed in these films. The Electron spin resonance performed at 35 GHz indicates the presence of oxygen in the surroundings of the paramagnetic defects. The spin density is of the order of some 1017 cm−3, independent of the growth pressure and in agreement with photothermal deflection spectroscopy results. From the IR spectroscopy and NRA one can deduce that most of the oxygen in the films is bound to silicon. Helium dilution of the plasma at 5 Pa tends to reduce the porosity and the oxygen contamination in the film but above 30% He dilution, the crystalline fraction decreases. When nitrogen is introduced into the plasma during growth the films become amorphous, even for very small partial pressures of N2.
Thin Solid Films, 2004
ABSTRACT
Thin Solid Films, 2005
The functionality and lifetime of thin film/substrate set depend mainly on its mechanical propert... more The functionality and lifetime of thin film/substrate set depend mainly on its mechanical properties. Probing and improving the thermomechanical behaviour (stability) are then of utmost importance. Amorphous carbon thin films, 320 nm thick, have been deposited by a sputtering technique on silicon wafers, 500 and 200 Am thick. The microstructure and the mechanical properties (hardness, indentation reduced modulus and average in-plane stresses) have been investigated using Raman and infrared spectroscopies, silicon curvature and nanoindentation experiments. In particular, the evolution of global stress in the film has been analysed in situ during an annealing treatment while the evolution of the mechanical response (elastic and plastic) induced by nitrogen post irradiations was surveyed by nanoindentation. We observed a rather good thermal stability of the film/substrate set and the presence of hydrogen in the film is discussed. Further, nitrogen irradiation and incorporation were observed to induce a dramatic decrease of the mechanical performance of the films. These behaviours are discussed in view of the thin film structure.
Thin Solid Films, 2003
Silicon layers were grown at 200 8C by reactive magnetron sputtering in a hydrogen-rich plasma (8... more Silicon layers were grown at 200 8C by reactive magnetron sputtering in a hydrogen-rich plasma (80% dilution). The samples were examined by Raman and infrared spectroscopies, as well as by transmission electron microscopy and optical transmission. In addition to the pronounced crystallization induced by the interactions with the H-based radicals, the incremental crystallization observed on the sample deposited in the region close to the cathode, where the radical density is high, appears due to the contribution of the incorporated Si nanopowders created in the surrounding plasma. The formation of these particles appeared, therefore, spatially limited because of its dependence on the radical density that is inhomogeneously distributed in the cathodesubstrate separating area. To some extent, this allows one to control their insertion, the growth rate and layer compactness, through variation of electrodes spacing, r.f. power and plasma pressure. The occurrence of both particle creation in the plasma and columnar growth in the bulk attests of the key role played by the highly sticking and reactive SiH .
Surface and Coatings Technology, 2012
We present in this study spectroscopic investigations of amorphous carbon nitride thin films (a-C... more We present in this study spectroscopic investigations of amorphous carbon nitride thin films (a-CN x) deposited on Si substrate by radio-frequency magnetron sputtering of a graphite target in Ar/N 2 gas mixture, under different deposition gas pressure. The properties of films were determined using atomic force microscopy (AFM), Fourier Transform Infrared measurements, transmission spectroscopy and intrinsic stress measurements. A limiting effect of the terminating bonds and their contamination by water has been examined in relation with optoelectronical and mechanical properties of the films. The appearance of the telephone-cord buckling as an interfacial failure mode has been elucidated and the evolution of their morphological characteristics has been studied in relation with the deposition conditions and the resulting microstructure.
Surface and Coatings Technology, 2006
The present paper deals with the characterization of plasma polymerized allylamine films. The fil... more The present paper deals with the characterization of plasma polymerized allylamine films. The films were characterized using a large panel of techniques such as Fourier transformation infrared spectroscopy, X-ray photoemission spectroscopy and ellipsometry. The film microstructure was investigated as a function of the deposition power while other process parameters (gas mixture flow, pressure) were kept constant. The microstructure shows a strong dependence on the deposition power. A power transition has been identified outlining two deposition modes in agreement with a growth model developed for carbon nitride thin films. Conditions of deposition closed to this transition provide a film microstructure interesting for absorption and adhesion of biomolecules i.e. high NH 2 content, high porosity and high deposition rate.
Solid State Communications, 2001
Carbon nitride (CN x) thin ®lms were deposited using RF magnetron sputtering technique of a graph... more Carbon nitride (CN x) thin ®lms were deposited using RF magnetron sputtering technique of a graphite target in a pure N 2 atmosphere at different RF power. Film composition was analysed using X-ray photoelectron spectroscopy measurements correlated with infrared absorption, Raman spectroscopy, optical transmission and photothermal de¯ection spectroscopy experiments. The observed variation of the optical properties are attributed to the changes in the atomic bonding structures, which were induced by ion bombardment, increasing both the sp 2 carbon content and their relative disorder.
Solid State Communications - SOLID STATE COMMUN, 2001
Carbon nitride (CNx) thin films were deposited using RF magnetron sputtering technique of a graph... more Carbon nitride (CNx) thin films were deposited using RF magnetron sputtering technique of a graphite target in a pure N2 atmosphere at different RF power. Film composition was analysed using X-ray photoelectron spectroscopy measurements correlated with infrared absorption, Raman spectroscopy, optical transmission and photothermal deflection spectroscopy experiments. The observed variation of the optical properties are attributed to the changes in the atomic bonding structures, which were induced by ion bombardment, increasing both the sp2 carbon content and their relative disorder.
Materials Science in Semiconductor Processing, 2001
ABSTRACT The subimplantation model was used to explain the formation of a-C:H films deposited fro... more ABSTRACT The subimplantation model was used to explain the formation of a-C:H films deposited from a dual ECR-RF discharge of methane–argon (5%) mixture at low pressure. Combined optical transmission measurements, elastic recoil detection analysis, Raman spectra and residual stress measurements are used to fully characterise the films as deposited. The residual stress vs. bias plot shows a behavior similar to those already obtained for tetrahedral amorphous carbon (ta-C) and tetrahedral hydrogenated amorphous carbon (ta-C:H) films. In this study, the ions sticking the film surface are not monoenergetic, the stress data matches the theoretical model proposed by Davis. The optimum energy obtained is similar to that obtained for tetrahedral films.
Materials Science and Engineering: B, 2003
Thin films of crystallized silicon were grown by reactive magnetron sputtering in a plasma of hyd... more Thin films of crystallized silicon were grown by reactive magnetron sputtering in a plasma of hydrogen-diluted argon with a degree varying in percentage from 0 to 100%. The effect of the cathode Á/substrate separating distance was also examined, while the deposition temperature was maintained at 200 8C. An amorphous-crystalline transition was found to take place at the early stages of hydrogenation (between 2 and 5%), followed by a columnar growth for higher dilution, as evidenced by Raman spectroscopy measurements and transmission electron microscopy (TEM). High-resolution TEM showed also evidence for the formation of nanosized Si grains in the cathode-near region of the plasma, where exist high density of hydride radicals produced with a high level of dilution in hydrogen. A part of the created nanopowders were found to incorporate the film growing in the region of polymerization reaction, allowing hence the possibility of some size-selection through variation of the cathode Á/substrate spacing distance.
Langmuir, 2006
In this article, we describe a method to create rough features on silicon surfaces by reactive et... more In this article, we describe a method to create rough features on silicon surfaces by reactive etching of a photoresist layer. The roughness and, consequently, the wettability of the surfaces can be modified by modifying the duration of plasma etching. Hydrophobic materials deposited on the rough silicon surface can be modified until a superhydrophobic behavior is obtained, whereas hydrophilic materials become more hydrophilic. The elaboration technique described herein offers an inexpensive and rapid method for the creation of tunable roughness on silicon surfaces with large areas.
Optics Communications
Abstract Hybrid one dimensional photonic crystal (1D PC) based on alternating layers of inorganic... more Abstract Hybrid one dimensional photonic crystal (1D PC) based on alternating layers of inorganic materials, the silicon (Si), grown by radiofrequency magnetron sputtering and organic compound, HMDSO mixed with nitrogen N 2 (HMDSO+N2), deposited by radiofrequency Plasma Enhanced Chemical Vapor Deposition (RF-PECVD) for different N 2 /HMDSO flow rate at a fixed power of 200W. As the refractive index of silicon (Si) is n=3.4, to obtain a good contrast index between the inorganic and organic layers leading to appearance of large photonic band gap, we have varied the flow of the mixed gaz (HMDSO+N2) for having a lower refractive index 1.7 corresponding to a layer with the same chemical composition element of the SiNOCH material as confirmed by IR measurement. After optimization of the Si and SiNOCH thickness layers with respect to the Bragg low, we have measured the photonic band gap (PBG) of Si/SiNOCH photonic structure through transmission and reflection spectra. The PBG appears after 5 periods of alternating layers with a width of 740 nm in the near infrared (NIR) region centered at 1500 nm. Our experimental results are interpreted successfully by a theoretical model based on the transfer matrix method (TMM).
Applied Surface Science
Abstract Electron-beam-induced deposition of various materials from suitable precursors has repre... more Abstract Electron-beam-induced deposition of various materials from suitable precursors has represented an established branch of nanotechnology for more than a decade. A specific alternative is carbon deposition on the basis of hydrocarbons as precursors that has been applied to grow various nanostructures including masks for subsequent technological steps. Our area of study was unintentional electron-beam-induced carbon deposition from spontaneously adsorbed hydrocarbon molecules. This process traditionally constitutes a challenge for scanning electron microscopy practice preventing one from performing any true surface studies outside an ultrahigh vacuum and without in-situ cleaning of samples, and also jeopardising other electron-optical devices such as electron beam lithographs. Here we show that when reducing the energy of irradiating electrons sufficiently, the e-beam-induced deposition can be converted to e-beam-induced release causing desorption of hydrocarbons and ultimate cleaning of surfaces in both an ultrahigh and a standard high vacuum. Using series of experiments with graphene samples, we demonstrate fundamental features of e-beam-induced desorption and present results of checks for possible radiation damage using Raman spectroscopy that led to optimisation of the electron energy for damage-free cleaning. The method of preventing carbon contamination described here paves the way for greatly enhanced surface sensitivity of imaging and substantially reduced demands on vacuum systems for nanotechnological applications.
Superlattices and Microstructures
Abstract Quasi-periodic one-dimensional Cantor photonic crystals are elaborated by depositing alt... more Abstract Quasi-periodic one-dimensional Cantor photonic crystals are elaborated by depositing alternating silicon and silica Si/SiO 2 layers by radiofrequency magnetron sputtering technique with cold plasma. Transmittance and reflectance spectra of these quasi crystals exhibit a large photonic band gap in the infrared range at normal incidence which is well reproduced by a theoretical model based on the transfer matrix method. The obtained wide photonic band gap reveals the existence of permitted modes depending on the nature and characteristics of the built in system which can constitute optical windows. This effect can be a good alternative for the design of flexible filters used in many areas of applications such as telecommunication and optoelectronic devices.
Solid State Communications, 2001
Analysis of carbon nitride ®lms (CN x) deposited by RF magnetron sputtering on crystalline silico... more Analysis of carbon nitride ®lms (CN x) deposited by RF magnetron sputtering on crystalline silicon, under different target selfbias, is reported. The properties of ®lms were determined in their as-deposited state using X-ray photoelectron spectroscopy (XPS), IR absorption, transmission spectroscopy and residual stress measurements. The presence of various types of C±N bonds, as well as of hydrogen and oxygen, is revealed. A good correlation is observed between the variation of N/C ratio, the optical gap E 04 and the internal stress as a function of the target bias. The optical gap E 04 decrease is discussed in terms of N/C ratio evolution, the sp 2 bond content and the local distortions of the sp 2 bonds.
Thin Solid Films, 2003
Analysis of carbon nitride films (CN) deposited by radio frequency (RF) magnetron sputtering on c... more Analysis of carbon nitride films (CN) deposited by radio frequency (RF) magnetron sputtering on crystalline silicon, under x different target self-bias, is reported. Plasma characterisation was performed using mass spectroscopy (MS) and the properties of films were determined in their as deposited state using elastic recoil detection analysis (ERDA), nuclear reaction analysis (NRA), X-ray photoelectron spectroscopy (XPS), infrared absorption, transmission spectroscopy and photothermal deflection spectroscopy (PDS) experiments. A good correlation is observed between the variation of NyC ratio and the growth rate. The resulting changes in the microstructure can be analyzed in terms of surface processes, nitrogen incorporation within the films and the Csp content. 2
Surface and Coatings Technology, 2002
ABSTRACT Analysis of carbon nitride films (CNx) deposited by RF magnetron sputtering on (100) sil... more ABSTRACT Analysis of carbon nitride films (CNx) deposited by RF magnetron sputtering on (100) silicon wafers, under different target self-bias, is reported. The properties of as-deposited films were determined using X-ray photoelectron spectroscopy (XPS), IR absorption, Raman spectra, transmission spectroscopy and photothermal deflexion spectroscopy (PDS). The presence of various types of CN bond, as well as of hydrogen and oxygen, was revealed. Good correlation was observed between the variation of nitrogen content (N/C ratio), the optical gap and the Raman features as a function of the target bias. The optical gap decrease is discussed in terms of N/C ratio evolution and the sp2 content.
The present work provides surface characterization for all steps involved in the fabrication of a... more The present work provides surface characterization for all steps involved in the fabrication of a direct label free piezoelectric immunoprobe, using techniques such as Ellipsometry, Atomic Force Microscopy, Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and X-Ray Photoelectron Spectroscopy (XPS). Active amino groups were successfully provided on the quartz crystal surface through plasma deposition of allylamine polymer film (ALL) [1] and were further utilised for antibody (Ab) immobilization. Results from this work show the possibility of producing simple, direct piezoelectric immunoprobes through appropriate antibody orientation without the need for labeled compounds. The combination of surface analytical, optical and mass balance techniques is confirming the effectiveness of these immunosensor fabrication strategies.
Solid State Phenomena, 2001
Vacuum, 2009
... 773782. Article | PDF (720 K) | View Record in Scopus | Cited By in Scopus (23). [3] Zaidi S... more ... 773782. Article | PDF (720 K) | View Record in Scopus | Cited By in Scopus (23). [3] Zaidi S, Lamarque F, Favergeon J, Carton O, Prelle C. Proc of Mecatronics, 2008, paper 143. [4] M. Boucinha, P. Brogueira, V. Chu and JP Conde, Appl Phys Lett 77 (No. 6) (2000), pp. ...
Thin Solid Films, 2004
ABSTRACT Nanocrystalline hydrogenated silicon films were grown by radiofrequency magnetron sputte... more ABSTRACT Nanocrystalline hydrogenated silicon films were grown by radiofrequency magnetron sputtering in an mixed Argon/Hydrogen (30%/70%) plasma. For some series Helium or Nitrogen was added to the gas mixture. The films were grown at 250 °C for total different pressures varying from 5 to 15 Pa. The crystalline fraction increases with pressure from 85 to 93% but at the same time the porosity of the films increases from 11 to 19%. This relatively high porosity leads to an important post-growth contamination of oxygen as revealed by IR absorption spectroscopy and nuclear reaction analysis (NRA) and can explain the low stress observed in these films. The Electron spin resonance performed at 35 GHz indicates the presence of oxygen in the surroundings of the paramagnetic defects. The spin density is of the order of some 1017 cm−3, independent of the growth pressure and in agreement with photothermal deflection spectroscopy results. From the IR spectroscopy and NRA one can deduce that most of the oxygen in the films is bound to silicon. Helium dilution of the plasma at 5 Pa tends to reduce the porosity and the oxygen contamination in the film but above 30% He dilution, the crystalline fraction decreases. When nitrogen is introduced into the plasma during growth the films become amorphous, even for very small partial pressures of N2.
Thin Solid Films, 2004
ABSTRACT
Thin Solid Films, 2005
The functionality and lifetime of thin film/substrate set depend mainly on its mechanical propert... more The functionality and lifetime of thin film/substrate set depend mainly on its mechanical properties. Probing and improving the thermomechanical behaviour (stability) are then of utmost importance. Amorphous carbon thin films, 320 nm thick, have been deposited by a sputtering technique on silicon wafers, 500 and 200 Am thick. The microstructure and the mechanical properties (hardness, indentation reduced modulus and average in-plane stresses) have been investigated using Raman and infrared spectroscopies, silicon curvature and nanoindentation experiments. In particular, the evolution of global stress in the film has been analysed in situ during an annealing treatment while the evolution of the mechanical response (elastic and plastic) induced by nitrogen post irradiations was surveyed by nanoindentation. We observed a rather good thermal stability of the film/substrate set and the presence of hydrogen in the film is discussed. Further, nitrogen irradiation and incorporation were observed to induce a dramatic decrease of the mechanical performance of the films. These behaviours are discussed in view of the thin film structure.
Thin Solid Films, 2003
Silicon layers were grown at 200 8C by reactive magnetron sputtering in a hydrogen-rich plasma (8... more Silicon layers were grown at 200 8C by reactive magnetron sputtering in a hydrogen-rich plasma (80% dilution). The samples were examined by Raman and infrared spectroscopies, as well as by transmission electron microscopy and optical transmission. In addition to the pronounced crystallization induced by the interactions with the H-based radicals, the incremental crystallization observed on the sample deposited in the region close to the cathode, where the radical density is high, appears due to the contribution of the incorporated Si nanopowders created in the surrounding plasma. The formation of these particles appeared, therefore, spatially limited because of its dependence on the radical density that is inhomogeneously distributed in the cathodesubstrate separating area. To some extent, this allows one to control their insertion, the growth rate and layer compactness, through variation of electrodes spacing, r.f. power and plasma pressure. The occurrence of both particle creation in the plasma and columnar growth in the bulk attests of the key role played by the highly sticking and reactive SiH .
Surface and Coatings Technology, 2012
We present in this study spectroscopic investigations of amorphous carbon nitride thin films (a-C... more We present in this study spectroscopic investigations of amorphous carbon nitride thin films (a-CN x) deposited on Si substrate by radio-frequency magnetron sputtering of a graphite target in Ar/N 2 gas mixture, under different deposition gas pressure. The properties of films were determined using atomic force microscopy (AFM), Fourier Transform Infrared measurements, transmission spectroscopy and intrinsic stress measurements. A limiting effect of the terminating bonds and their contamination by water has been examined in relation with optoelectronical and mechanical properties of the films. The appearance of the telephone-cord buckling as an interfacial failure mode has been elucidated and the evolution of their morphological characteristics has been studied in relation with the deposition conditions and the resulting microstructure.
Surface and Coatings Technology, 2006
The present paper deals with the characterization of plasma polymerized allylamine films. The fil... more The present paper deals with the characterization of plasma polymerized allylamine films. The films were characterized using a large panel of techniques such as Fourier transformation infrared spectroscopy, X-ray photoemission spectroscopy and ellipsometry. The film microstructure was investigated as a function of the deposition power while other process parameters (gas mixture flow, pressure) were kept constant. The microstructure shows a strong dependence on the deposition power. A power transition has been identified outlining two deposition modes in agreement with a growth model developed for carbon nitride thin films. Conditions of deposition closed to this transition provide a film microstructure interesting for absorption and adhesion of biomolecules i.e. high NH 2 content, high porosity and high deposition rate.
Solid State Communications, 2001
Carbon nitride (CN x) thin ®lms were deposited using RF magnetron sputtering technique of a graph... more Carbon nitride (CN x) thin ®lms were deposited using RF magnetron sputtering technique of a graphite target in a pure N 2 atmosphere at different RF power. Film composition was analysed using X-ray photoelectron spectroscopy measurements correlated with infrared absorption, Raman spectroscopy, optical transmission and photothermal de¯ection spectroscopy experiments. The observed variation of the optical properties are attributed to the changes in the atomic bonding structures, which were induced by ion bombardment, increasing both the sp 2 carbon content and their relative disorder.
Solid State Communications - SOLID STATE COMMUN, 2001
Carbon nitride (CNx) thin films were deposited using RF magnetron sputtering technique of a graph... more Carbon nitride (CNx) thin films were deposited using RF magnetron sputtering technique of a graphite target in a pure N2 atmosphere at different RF power. Film composition was analysed using X-ray photoelectron spectroscopy measurements correlated with infrared absorption, Raman spectroscopy, optical transmission and photothermal deflection spectroscopy experiments. The observed variation of the optical properties are attributed to the changes in the atomic bonding structures, which were induced by ion bombardment, increasing both the sp2 carbon content and their relative disorder.
Materials Science in Semiconductor Processing, 2001
ABSTRACT The subimplantation model was used to explain the formation of a-C:H films deposited fro... more ABSTRACT The subimplantation model was used to explain the formation of a-C:H films deposited from a dual ECR-RF discharge of methane–argon (5%) mixture at low pressure. Combined optical transmission measurements, elastic recoil detection analysis, Raman spectra and residual stress measurements are used to fully characterise the films as deposited. The residual stress vs. bias plot shows a behavior similar to those already obtained for tetrahedral amorphous carbon (ta-C) and tetrahedral hydrogenated amorphous carbon (ta-C:H) films. In this study, the ions sticking the film surface are not monoenergetic, the stress data matches the theoretical model proposed by Davis. The optimum energy obtained is similar to that obtained for tetrahedral films.
Materials Science and Engineering: B, 2003
Thin films of crystallized silicon were grown by reactive magnetron sputtering in a plasma of hyd... more Thin films of crystallized silicon were grown by reactive magnetron sputtering in a plasma of hydrogen-diluted argon with a degree varying in percentage from 0 to 100%. The effect of the cathode Á/substrate separating distance was also examined, while the deposition temperature was maintained at 200 8C. An amorphous-crystalline transition was found to take place at the early stages of hydrogenation (between 2 and 5%), followed by a columnar growth for higher dilution, as evidenced by Raman spectroscopy measurements and transmission electron microscopy (TEM). High-resolution TEM showed also evidence for the formation of nanosized Si grains in the cathode-near region of the plasma, where exist high density of hydride radicals produced with a high level of dilution in hydrogen. A part of the created nanopowders were found to incorporate the film growing in the region of polymerization reaction, allowing hence the possibility of some size-selection through variation of the cathode Á/substrate spacing distance.
Langmuir, 2006
In this article, we describe a method to create rough features on silicon surfaces by reactive et... more In this article, we describe a method to create rough features on silicon surfaces by reactive etching of a photoresist layer. The roughness and, consequently, the wettability of the surfaces can be modified by modifying the duration of plasma etching. Hydrophobic materials deposited on the rough silicon surface can be modified until a superhydrophobic behavior is obtained, whereas hydrophilic materials become more hydrophilic. The elaboration technique described herein offers an inexpensive and rapid method for the creation of tunable roughness on silicon surfaces with large areas.