Nano-Structured Amorphous Carbon Films Synthesised Using Decr Plasma

2001 ◽  
Vol 675 ◽  
Author(s):  
André Golanski ◽  
Dieter Grambole ◽  
Jean Hommet ◽  
Folker Herrmann ◽  
Philippe Kern ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electron Cyclotron Resonance ◽  
Plasma Reactor ◽  
Argon Plasma ◽  
Carbon Films ◽  
Plasma Pressure ◽  
Nuclear Reaction Analysis ◽  
Elastic Recoil ◽  
Si Substrates ◽  
Detection Analysis

ABSTRACTA Distributed Electron Cyclotron Resonance plasma reactor powered by a microwave generator operating at 2.45 GHz was used to deposit ta-C:H (Diamond-Like Carbon, DLC) thin films at RT. A graphite sputtering target immersed in an argon plasma was used as carbon source. The Ar plasma density was about 5×1010 cm-3. Single crystal <100> Si substrates were RF biased to a negative voltage of -80 V. Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), nuclear reaction analysis (NRA) using the resonance at 6.385 MeV of the reaction: 15N + 1H-→ 12C + 4He + γ, elastic recoil detection analysis (ERDA) and Rutherford backscattering (RBS) were used to investigate the early phase of the growth. The morphology of the films grown at low pressure (0.3 mTorr) is shown to be dominated by stress-mediated nucleation leading to formation of basket-like clusters of circular hillocks 20 nm high surrounded by a planar, mostly sp2 bonded film ∼8 nm thick. With increasing plasma pressure the spatial frequency of the hillocks becomes random and the growth is dominated by the Stranski-Krastanov mode. The XPS data taken at decreasing emergence angles show that the structure of the hillocks is dominated by sp3 bonded carbon. The XPS argon signal disappears at 10° emergence angle indicating that integration of argon occurs mainly within the sp bonded regions. The NRA and ERDA analysis show that the amount of integrated hydrogen decreases with increasing substrate current density. RBS data indicate that increasing bias enhances argon integration.

Incorporation of Hydrogen and Oxygen into (t)a-C:H Thin Films Deposited using DECR plasma (*)

2001 ◽  
Vol 675 ◽  
Author(s):  
Fabrice Piazza ◽  
Dieter Grambole ◽  
Folker Herrmann ◽  
Gary Relihan ◽  
Marie France Barthe ◽  
...  
Keyword(s):  
Thin Films ◽  
Hydrogen Content ◽  
Electron Cyclotron Resonance ◽  
Plasma Reactor ◽  
Positron Annihilation Spectroscopy ◽  
Plasma Pressure ◽  
Nuclear Reaction Analysis ◽  
Hydrogen Incorporation ◽  
Si Substrates ◽  
Deposited Energy

ABSTRACTA distributed electron cyclotron resonance (DECR) plasma reactor powered by a microwave generator operating at 2.45 GHz (800 W) was used to deposit (t)a-C:H thin films at RT on <100> Si substrates RF biased within the range 25≤|V0|≤600 V.C2H2 was used as precursor. The plasma pressure was varied within the range 0.1≤P≤1.5 mtorr. The films were analysed using spectroscopic ellipsometry (SE) and Fourier transform infrared (FTIR) spectroscopy. The hydrogen content NH and the density of the films were determined from nuclear reaction analysis (NRA) using the resonance at 6.385 MeV of the reaction: 15N + 1H → 12C + 4He + γ. Positron annihilation spectroscopy was used to detect the porosity. The evolutions of NH as a function of the substrate ion current density n+ and as a function of V0 show that the hydrogen incorporation results from the competition between chemisorption and deposited energy density related effects. The increase of the hydrogen incorporation leads to a decrease in the film density and a lower deposition rate. The porosity of the films deposited at low pressure (∼0.1 mTorr) with V0= −80 V has been detected. The comparison between results of SRIM-2000 simulations and the evolution of NH as a function of V0 shows that the porosity and the hydrogen content are not correlated. The absorption of oxygen and nitrogen for the low density films has been detected from the observation of the 3250–4000 cm-1infra-red (IR) band.

scholarly journals Morphology, Microstructure, and Hydrogen Content of Carbon Nanostructures Obtained by PECVD at Various Temperatures

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
M. Acosta Gentoiu ◽  
R. Betancourt-Riera ◽  
S. Vizireanu ◽  
I. Burducea ◽  
V. Marascu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Carbon Nanostructures ◽  
Strong Dependence ◽  
Argon Plasma ◽  
Elastic Recoil ◽  
Elastic Recoil Detection ◽  
Detection Analysis ◽  
Transmission Electron ◽  
Aligned Carbon Nanotubes

Carbon nanostructures were obtained by acetylene injection into an argon plasma jet in the presence of hydrogen. The samples were synthesized in similar conditions, except that the substrate deposition temperatures TD were varied, ranging from 473 to 973 K. A strong dependence of morphology, structure, and graphitization upon TD was found. We obtained vertical aligned carbon nanotubes (VA-CNTs) at low temperatures as 473 K, amorphous carbon nanoparticles (CNPs) at temperatures from about 573 to 673 K, and carbon nanowalls (CNWs) at high temperatures from 773 to 973 K. Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, elastic recoil detection analysis, X-ray photoelectron spectroscopy, and Raman spectroscopy were used to substantiate the differences in these material types. It is known that hydrogen concentration modifies strongly the properties of the materials. Different concentrations of hydrogen-bonded carbon could be identified in amorphous CNP, VA-CNT, and CNW. Also, the H : C ratios along depth were determined for the obtained materials.

Composition and Structure of Epitaxial CaF2 Layers at the First Stages of Their Growth on Si(111)

2001 ◽  
Vol 696 ◽  
Author(s):  
R. Würz ◽  
W. Bohne ◽  
W. Fuhs ◽  
J. Röhrich ◽  
M. Schmidt ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Film Growth ◽  
Stoichiometric Composition ◽  
Interface Reaction ◽  
Heavy Ion ◽  
Interface Layer ◽  
Buffer Layers ◽  
Ex Situ ◽  
Elastic Recoil ◽  
Detection Analysis

AbstractCaF2 films with thicknesses in the monolayer range (<20 Å) were grown on Si(111) by evaporation from a CaF2 source at UHV conditions. They were characterized ex-situ by Heavy-Ion Elastic Recoil Detection Analysis (HI-ERDA), RBS/Channeling, X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM). The F/Ca ratio of the films was found to depend on the growth temperature Ts and to deviate appreciably from the stoichiometric composition (F/Ca=2). Due to an interface reaction which leads to a CaF-interface layer a change from polycrystalline to epitaxial growth occurs at Ts=450°C. At higher temperature film growth started with a closed layer of CaF on top of which CaF2 layers with an increasing fraction of pinholes were formed. By means of a two-step process at different temperatures, the amount of pinholes could be strongly reduced. It was found, that buffer layers of CaF2 with a CaF interface layer introduced in Au/p-Si contacts enhance the barrier height by as much as 0.36eV to values of 0.64eV.

Single Source CVD of LiAlO2

1997 ◽  
Vol 495 ◽  
Author(s):  
Wonyong Koh ◽  
Su-Jin Ku ◽  
Yunsoo Kim
Keyword(s):  
Photoelectron Spectroscopy ◽  
Profile Analysis ◽  
Chemical Vapor ◽  
Single Source ◽  
Elastic Recoil ◽  
Elastic Recoil Detection ◽  
Si Substrates ◽  
Metal Contents ◽  
Deposited Film ◽  
Heterometallic Compound

ABSTRACTWe successfully deposited LiAlO2 films on Si substrates at 400–600 °C by single source chemical vapor deposition using a heterometallic compound, Li(O'Pr)2Al(CH3)2, which contains Li, Al, and O at the same 1:1:2 ratio as LiAlO2. Li(O'Pr)2Al(CH3)2 is sufficiently volatile to be vapor-transported at 50 °C. Elastic recoil detection and Rutherford backscattering spectroscopy analyses of a deposited film indicate that the film is stoichiometric (Li:Al:O = 1.0:1.0:2.0) and contains a few atomic percent hydrogen (5 %) and carbon (2 %). Depth profile analysis of X-ray photoelectron spectroscopy also confirms the 1:1 ratio of metal contents in the films. As-deposited films were amorphous, however, crystallized to β- or γ-LiA1O2 after annealing at 950 °C.

scholarly journals Verification Study of Nanostructure Evolution with Heating Treatment between Thin and Thick Fullerene-Like Hydrogen Carbon Films

Coatings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 82 ◽  
Author(s):  
Zhaolong Wang ◽  
Kaixiong Gao ◽  
Bin Zhang ◽  
Zhenbin Gong ◽  
Xiaoli Wei ◽  
...  
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Thick Films ◽  
Carbon Films ◽  
Good Choice ◽  
Xps Spectra ◽  
Si Substrates ◽  
Transmission Electron ◽  
Original Films ◽  
Heating Treatment

Fullerene-like hydrogen carbon films with a thin film grown on a NaCl substrate are usually employed to show the nanostructure of films (usually of hundred nanometers thick grown on Si substrates) under high resolution transmission electron microscopy (HRTEM) tests because it is easier floated off, where dependability and reasonability has never been seriously contested. Thus, in this paper, thin and thick hydrogen carbon films have been deposited on NaCl (thin films) and Si (thick films) substrates and annealed under room temperature to 500 °C, of which nanostructures have been investigated by HRTEM, Raman spectroscopy, and X-ray photoelectron spectroscopy, to verify the dependability and reasonability of the NaCl method. The results showed heating induced graphitization but with hydrogen content nearly unchanged. HRTEM results revealed that under annealing of 200, 250, and 300 °C, the curved graphene structures gradually increase in films. However, beyond 400 °C, onions structures are present. However, both Raman and XPS spectra show us that after annealed treatment, for original films, both thin and thick films have the near sp2 bonding content and size, but with the annealing temperature increase, sp2 bonding content increases more quickly for thick FL-C:H films due to the higher internal stress compared to thin films. In one word, the NaCl method used for nanostructure detection for films might be a good choice for an easier and quicker analysis, but it is still insufficient, because the heating effect induced by plasma cannot be ignored.

Characterization and Tribological Properties of Nanostructured Copper/Carbon Composite Films Prepared by Microwave Plasma-Assisted Dual Deposition Processes

2002 ◽  
Vol 750 ◽  
Author(s):  
François Thiery ◽  
Yves Pauleau ◽  
Jacques Pelletier
Keyword(s):  
Amorphous Carbon ◽  
Electron Cyclotron Resonance ◽  
Microwave Plasma ◽  
Plasma Reactor ◽  
Composite Films ◽  
Chemical Vapor ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Carbon Films ◽  
Radius Of Curvature

ABSTRACTNanocrystalline copper/hydrogenated amorphous carbon films have been deposited on Si substrates at the floating potential using a distributed electron cyclotron resonance microwave plasma reactor. In this deposition technique, the microwave plasma-enhanced chemical vapor deposition process of carbon from argon-methane or argon-acetylene mixtures of various compositions was associated with the sputter deposition of copper from a copper target. The total pressure was fixed at 0.13 Pa. For deposition, the substrates mounted on a water-cooled substrate holder were maintained at ambient temperature. The composition of films determined by Rutherford backscattering spectroscopy, energy recoil detection analyses and nuclear reaction analyses was investigated as a function of the gas phase composition. The structure of films was identified by X-ray diffraction (XRD) techniques and the size of copper crystallites incorporated in the amorphous carbon matrix was deduced from XRD data. The magnitude of residual stresses developed in these films was calculated from the radius of curvature of film/substrate samples determined by profilometry. The residual stress values were found to be nearly independent on the composition of films and deposition parameters.

Characterization of Microcrystalline Si Films by MeV Ion Scattering Techniques

2000 ◽  
Vol 638 ◽  
Author(s):  
W. Bohne ◽  
J. Röhrich ◽  
B. Selle ◽  
M. Birkholz ◽  
F. Fenske ◽  
...  
Keyword(s):  
Electron Cyclotron Resonance ◽  
Ion Beam ◽  
Impurity Content ◽  
Heavy Ion ◽  
Ion Scattering ◽  
Elastic Recoil ◽  
Interference Structure ◽  
Detection Analysis ◽  
Apparent Similarity ◽  
Si Films

AbstractRutherford Backscattering Spectroscopy (RBS) and channeling studies with 1.4 MeV−4He ions as well as Heavy-Ion Elastic Recoil Detection Analysis (HI-ERDA) with 230 MeV 129Xe ions have been applied to characterize structural properties and the impurity content of thin Si films. The analytical potential of these ion-beam techniques is demonstrated for two types of samples: (1) μc-Si films prepared by dc magnetron sputtering in a pure Ar plasma and (2) homoepitaxial Si films deposited by low-temperature electron-cyclotron resonance PECVD at the transition from oriented to disordered growth. For μc-Si the atomic area density N.d obtained by RBS was compared with the optical thickness n.d (n=refractive index) derived from the interference structure of IR reflection spectra. It is shown that the ratio R=n.d/N.d of these quantities can serve as a figure of merit for the degree of crystalline order. An apparent similarity was found in the case of the epitaxially grown films between the Si disorder profiles evaluated from the RBS channeling spectra and the hydrogen and oxygen profiles determined by HI-ERDA. This suggests that hydrogen and oxygen are preferentially incorporated in the disordered parts of the films.

scholarly journals Study of Synchrotron Radiation Near-Edge X-Ray Absorption Fine-Structure of Amorphous Hydrogenated Carbon Films at Various Thicknesses

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Sarayut Tunmee ◽  
Ratchadaporn Supruangnet ◽  
Hideki Nakajima ◽  
XiaoLong Zhou ◽  
Satoru Arakawa ◽  
...  
Keyword(s):  
Fine Structure ◽  
Film Thickness ◽  
Rutherford Backscattering Spectrometry ◽  
Carbon Films ◽  
Elastic Recoil ◽  
X Ray ◽  
Absorption Fine ◽  
Detection Analysis ◽  
X Ray Absorption ◽  
Amorphous Hydrogenated Carbon

The compositions and bonding states of the amorphous hydrogenated carbon films at various thicknesses were evaluated via near-edge X-ray absorption fine-structure (NEXAFS) and elastic recoil detection analysis combined with Rutherford backscattering spectrometry. The absolute carbonsp2contents were determined to decrease to 65% from 73%, while the hydrogen contents increase from 26 to 33 at.% as the film thickness increases. In addition, as the film thickness increases, theπ⁎(C=C),σ⁎(C–H),σ⁎(C=C), andσ⁎(C≡C) bonding states were found to increase, whereas theπ⁎(C≡C) andσ⁎(C–C) bonding states were observed to decrease in the NEXAFS spectra. Consequently, the film thickness is a key factor to evaluate the composition and bonding state of the films.

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