DEPOSITION OF WIDE BAND GAP DLC FILMS USING R.F. PECVD AT VERY LOW POWER

2011 ◽  
Vol 25 (29) ◽  
pp. 3941-3949 ◽  
Author(s):  
P. K. BARHAI ◽  
RISHI SHARMA ◽  
B. B. NAYAK
Keyword(s):  
Band Gap ◽  
Chemical Vapor ◽  
Wide Band ◽  
Carbon Films ◽  
Wide Band Gap ◽  
Force Microscopy ◽  
Atomic Force ◽  
Frequency Plasma ◽  
Bending Modes ◽  
Deposited Films

Wide band gap diamond-like carbon films (DLCs) are deposited on silicon (1 0 0) substrates using capacitive coupled radio frequency plasma-enhanced chemical vapor deposition (R.F. PECVD) technique. The deposition of films is carried out at a constant pressure (~5×10-2 mbar ) using acetylene precursor diluted with argon at constant R.F. power of 5 W. Raman spectroscopy of deposited DLC films shows broad G peak near 1550 cm-1 and a weak D peak near 1320 cm1. FTIR plot of DLC films shows a peak near 2900 cm-1 corresponding to C–H stretching mode and peaks below 2000 cm-1 corresponding to C–C modes and C–H bending modes. Maximum hardness of the deposited films is found to be ~15 GPa. Band gap of the DLC films is ~3.5 eV. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) pictures show that the deposited films are amorphous. Deposition mechanism of wide band gap DLC film is explained on the basis of subplantation model.

Stress origin and relaxation in epitaxial AlN thin films on SiC

2001 ◽  
Vol 696 ◽  
Author(s):  
Ravi Bathe ◽  
R.D. Vispute ◽  
Daniel Habersat ◽  
R. P. Sharma ◽  
T. Venkatesan ◽  
...  
Keyword(s):  
Thin Films ◽  
Rutherford Backscattering Spectrometry ◽  
Wide Band ◽  
X Ray Diffraction ◽  
Wide Band Gap ◽  
X Ray ◽  
Force Microscopy ◽  
Ion Channeling ◽  
Atomic Force ◽  
Highly Strained

AbstractWe have investigated the epitaxy, surfaces, interfaces, and defects in AlN thin films grown on SiC by pulsed laser deposition. The stress origin, evolution, and relaxation in these films is reported. The crystalline structure and surface morphology of the epitaxially grown AlN thin films on SiC (0001) substrates have been studied using x-ray diffraction (θ–2θ, ω, and Ψ scans) and atomic force microscopy, respectively. The defect analysis has been carried out by using Rutherford backscattering spectrometry and ion channeling technique. The films were grown at various substrate temperatures ranging from room temperature to 1100 °C. X-ray diffraction measurements show highly oriented AlN films when grown at temperatures of 750- 800 °C, and single crystals above 800 °C. The films grown in the temperature range of 950 °C to 1000 °C have been found to be highly strained, whereas the films grown above 1000 °C were found to be cracked along the crystallographic axes. The results of stress as a function of growth temperature, thermal mismatch, growth mode, and buffer layer thickness will be presented, and the implications of these results for wide band gap power electronics will be discussed.

Numerical Analysis of Thermal Stresses in Carbon Films Obtained by the Rf Pecvd Method on the Surface of a Cannulated Screw / Analiza Numeryczna Naprezen Cieplnych W Warstwie Weglowej Otrzymanej W Procesie Rf Pecvd Na Powierzchni Wkreta Kostnego

2013 ◽  
Vol 58 (1) ◽  
pp. 77-81 ◽  
Author(s):  
J. Sawicki ◽  
M. Dudek ◽  
Ł. Kaczmarek ◽  
B. Wiecek ◽  
B. Swiatczak ◽  
...  
Keyword(s):  
Thermal Stresses ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Cannulated Screw ◽  
Radio Frequency Plasma ◽  
Medical Implants ◽  
Total Destruction ◽  
Frequency Plasma ◽  
Deposited Films ◽  
Film Interface

For many years, research on carbon films has been stimulated by the need to simultaneously optimize their biological and mechanical properties and by the challenges related to their deposition on medical implants. The residual mechanical stress occurring inside deposited films is the most important mechanical parameter which leads to the total destruction of these films by cracking and peeling. In the present work, we systematically studied the effect of ion bombardment during the process of radio frequency plasma enhanced chemical vapor deposition (RF PECVD) by monitoring the temperature distribution on a cannulated screw using the infrared technique. The obtained experimental and finite element modeling (FEM) results show that stresses in carbon films deposited on a cannulated screw are quite inhomogeneous and depend on the geometry of the sample and the relative position of the studied contact area between the substrate/film interface and the surface of the film.

Hydrogenated Amorphous Silicon-Nitrogen, a-Si,N:H ALLOYS: An Alternative to A-SI,C:H for the Wide Band Gap Photo-Active Material in Tandem PV Cells

1993 ◽  
Vol 297 ◽  
Author(s):  
M.J. Williams ◽  
S.M. Cho ◽  
G. Lucovsky
Keyword(s):  
Chemical Vapor Deposition ◽  
Band Gap ◽  
Vapor Deposition ◽  
Active Material ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Wide Band ◽  
Wide Band Gap ◽  
Staebler Wronski Effect ◽  
Hydrogenated Amorphous

We have investigated a-Si,N:H alloys as an alternative wide band-gap, photo-active material. The entire alloy range between a-Si:H and a-Si3N4:H can be formed by a remote plasma-enhanced chemical-vapor deposition (PECVD) process. Other studies have demonstrated that a-Si,N:H alloys could be doped to form window materials for p-i-n devices. This paper focuses on alloy materials with E04 bandgaps to about 2.2 eV. We have prepared these a-Si,N:H alloys, characterized their microstructure, and studied their photoconductivity, sensitivity to light-soaking and transport properties. For example, with increased alloying we show that i) the white-light photoconductivity and ii) the kinetics and magnitude of the decay of photoconducitivity under intense illumination (the Staebler-Wronski effect), are about the same as for PV-grade a-Si:H.

Epitaxial growth of wide-band-gap ZnGa2O4 films by mist chemical vapor deposition

2014 ◽  
Vol 386 ◽  
pp. 190-193 ◽  
Author(s):  
Takayoshi Oshima ◽  
Mifuyu Niwa ◽  
Akira Mukai ◽  
Tomohito Nagami ◽  
Toshihisa Suyama ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Band Gap ◽  
Epitaxial Growth ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Wide Band ◽  
Wide Band Gap

scholarly journals Evidence of Carboxyl Modification of Hydrogen-Free Diamond-Like Carbon Films Assisted by Radio Frequency Plasma in Vacuum

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Yuqi Xue ◽  
Zixin Wang ◽  
Jun Wang ◽  
Changji Hu ◽  
Fangyan Xie ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Carbon Films ◽  
Rf Plasma ◽  
Diamond Like Carbon ◽  
Spectra Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Frequency Plasma ◽  
Ft Ir

Modification of hydrogen-free diamond-like carbon (DLC) is presented, with acrylic acid (AA) vapor carried into a vacuum chamber by argon and with the in situ assistance of low-power radio frequency (RF) plasma at a temperature below 100°C. Measured by atomic force microscopy (AFM) technique, the roughness (Ra) of the DLC was 1.063±0.040 nm. XPS and FT-IR spectra analysis showed that carboxyl groups were immobilized on the surface of the DLC films, with about 40% of carboxyl group area coverage. It was found that the RF plasma and reaction time are important in enhancing the modification rate and efficiency.

scholarly journals Topography and nanomechanical properties of Pd-C films

Open Physics ◽  
2011 ◽  
Vol 9 (2) ◽  
Author(s):  
Joanna Rymarczyk ◽  
Elzbieta Czerwosz ◽  
Asta Richter
Keyword(s):  
Chemical Vapor ◽  
Carbon Films ◽  
Fused Silica ◽  
Indentation Modulus ◽  
Force Microscopy ◽  
Nanomechanical Properties ◽  
Atomic Force ◽  
Nanoindentation Experiment ◽  
Chemical Vapor Decomposition ◽  
Palladium Content

AbstractAtomic force microscopy (AFM) topographical studies and results of nanoindentation experiment for several palladium-carbon films (Pd-C film) deposited on various substrates and with varying palladium content are presented. Pd-C films were prepared by a physical vapor decomposition (PVD) process and next were modified by a chemical vapor decomposition (CVD) method to obtain carbonaceous porous structure with dispersed palladium nanograins and a variation in roughness.The dependence of film topography on the kind of substrate such as Al2O3, Mo polycrystalline foil and fused silica was studied by AFM. Nanomechanical properties such as hardness and the reduced indentation modulus were determined by nanoindentation. A comparison of these values for films with different Pd content deposited on various substrates is presented.

scholarly journals Effects of Annealing Temperature on Optical Band Gap of Sol-gel Tungsten Trioxide Films

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 377 ◽  
Author(s):  
Guanguang Zhang ◽  
Kuankuan Lu ◽  
Xiaochen Zhang ◽  
Weijian Yuan ◽  
Muyang Shi ◽  
...  
Keyword(s):  
Band Gap ◽  
Tungsten Trioxide ◽  
Annealing Temperature ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Wide Band ◽  
X Ray Diffraction ◽  
Electrochromic Devices ◽  
Wide Band Gap ◽  
Atomic Force

Tungsten trioxide (WO3) is a wide band gap semiconductor material that is used as an important electrochromic layer in electrochromic devices. In this work, the effects of the annealing temperature on the optical band gap of sol-gel WO3 films were investigated. X-ray Diffraction (XRD) showed that WO3 films were amorphous after being annealed at 100 °C, 200 °C and 300 °C, respectively, but became crystallized at 400 °C and 500 °C. An atomic force microscope (AFM) showed that the crystalline WO3 films were rougher than the amorphous WO3 films (annealed at 200 °C and 300 °C). An ultraviolet spectrophotometer showed that the optical band gap of the WO3 films decreased from 3.62 eV to 3.30 eV with the increase in the annealing temperature. When the Li+ was injected into WO3 film in the electrochromic reaction, the optical band gap of the WO3 films decreased. The correlation between the optical band gap and the electrical properties of the WO3 films was found in the electrochromic test by analyzing the change in the response time and the current density. The decrease in the optical band gap demonstrates that the conductivity increases with the corresponding increase in the annealing temperature.

Growth Control And Characterization Of Wide Band Gap Silicon-Carbon Films

1997 ◽  
Vol 483 ◽  
Author(s):  
S. Kerdiles ◽  
R. Rizk ◽  
A. Pérez-Rodríguez ◽  
B. Garrido ◽  
O. González-Varona ◽  
...  
Keyword(s):  
Band Gap ◽  
Photoelectron Spectroscopy ◽  
Stoichiometric Composition ◽  
Growth Control ◽  
Wide Band ◽  
Atomic Ratio ◽  
Carbon Films ◽  
Wide Band Gap ◽  
Silicon Carbon ◽  
Amorphous Sic

AbstractSilicon-carbon films have been grown by reactive hydrogen magnetron sputtering at a substrate temperature of 730°C, with different values of carbon-to-silicon sputtered area ratio, rc. The layers were investigated by infrared spectroscopy, Raman scattering, x-ray photoelectron spectroscopy and optical absorption. For rc below 30%, almost only Si nanocrystallites were formed with a few fraction of amorphous SiC, whereas for rc exceeding 30%, a drastic change was noticed, leading to the achievement of SiC crystals in the layers. These latter were found of near-stoichiometric composition with an atomic ratio C/Si ˜1.04. The results suggest that the excess C is of graphitic-like configuration being likely located in the intergrain regions, in addition to some silicon-oxygen bonds. These features are accompanied by an abrupt widening of the band gap in the transition region that is consistent with the formation of SiC nanocrystals. The large value measured for the band gap (≥3 eV) is thought to be due to more than one origin, such as size effect of SiC, Si-O bonds and possible presence of different SiC polytypes.

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