The Influence of Frequency and Pressure on the Material Quality of PECVD A-SI:H

1995 ◽  
Vol 377 ◽  
Author(s):  
W.G.J.H.M. Van Sark ◽  
J. Bezemer ◽  
E. M. B. Heller ◽  
M. Kars ◽  
W. F. Van Der Weg
Keyword(s):  
Vapour Deposition ◽  
Chemical Vapour ◽  
Clear Correlation ◽  
Frequency Variation ◽  
Process Conditions ◽  
Optimum Pressure ◽  
Quality Requirements ◽  
Material Quality ◽  
Better Than

ABSTRACTA systematic study of material quality has been performed for a-Si:H layers deposited by plasma enhanced chemical vapour deposition at frequencies between 30–80 MHz. The effect of frequency variation was studied in combination with the variation of pressure and power density. The process conditions were optimised not only for ‘device quality’ opto-electronic properties but also for a uniformity in layer thickness better than 5 %. For every frequency an optimum pressure exists for which the properties of the deposited layer satisfy the ‘device quality’ requirements. A clear correlation is observed between the transition from the so-called α- to the γ-regime of the plasma and the dependence of the deposition rate γd with pressure pand frequency ƒ: γ d ∝ pƒ2/3.

Rbs and Pixe Analysis Of Hg1-xCdxTe grown by MOCVD.

1990 ◽  
Vol 216 ◽  
Author(s):  
S.P. Russo ◽  
R.G. Elliman ◽  
P.N. Johnston ◽  
G.N. Pain
Keyword(s):  
Gas Flow ◽  
Vapour Deposition ◽  
Rutherford Backscattering Spectrometry ◽  
Chemical Vapour ◽  
Organic Chemical ◽  
Pixe Analysis ◽  
Mocvd Reactor ◽  
Metal Organic ◽  
Thickness Variations

ABSTRACTThe techniques, Particle Induced X-ray Emission (PIXE) and Rutherford Backscattering Spectrometry (RBS) have been used to investigate compositional and thickness uniformity of Hg1-xCdxTe (MCT) grown on GaAs substrates by Metal Organic Chemical Vapour Deposition (MOCVD). Composition and thickness variations are reported for orientations perpendicular and parallel to gas flow in the MOCVD reactor. Crystalline quality of the MCT layer was also determined by RBS channelling analysis.

The Influence of the Carbonization Mechanisms on the Crystalline Quality of the Carbonization Layer for Heteroepitaxial Growth of 3C-SiC

2014 ◽  
Vol 778-780 ◽  
pp. 230-233
Author(s):  
Yukimune Watanabe ◽  
Tsuyoshi Horikawa ◽  
Kiichi Kamimura
Keyword(s):  
Diffusion Mechanism ◽  
Growth Direction ◽  
Crystalline Quality ◽  
Process Conditions ◽  
Heteroepitaxial Growth ◽  
Crystal Axis ◽  
Si Substrates ◽  
Selected Area Electron Diffraction ◽  
Better Than

The carbonized layer for a buffer layer strongly influences the crystalline quality of the 3C-SiC epitaxial films on the Si substrates. The growth mechanism of the carbonized layer strongly depended on the process conditions. The surface of silicon substrate was carbonized under the pressure of 7.8 × 10-3 Pa or 7.8 × 10-2 Pa in this research. Under the relatively low pressure of 7.8 × 10-3 Pa, the carbonized layer was grown by the epitaxial mechanism. The crystal axis of the carbonized layer grown under this pressure was confirmed to coincide with the crystal axis of the Si substrate from the results of the selected area electron diffraction (SAED) analysis. Under the relatively high pressure condition of 7.8 × 10-2 Pa, the carbonized layer was grown by the diffusion mechanism. The result of the SAED pattern and the XTEM image indicated that this layer consisted of small grainy crystals and their crystal axes inclined against the growth direction. It was confirmed that the crystalline quality of the SiC film deposited on the carbonized layer grown by the epitaxial mechanism is better than that deposited on the layer grown by the diffusion mechanism.

scholarly journals The Range Values for the Design Parameters of Nanoengineered Concrete Components. Characteristics, Properties, Amounts and Effects on the Concrete Behaviour

2013 ◽  
Vol 8-9 ◽  
pp. 277-284
Author(s):  
Olar Radu ◽  
Traian Onet
Keyword(s):  
Compressive Strength ◽  
Structural Material ◽  
Real Time ◽  
New Products ◽  
Structural Behavior ◽  
Design Parameters ◽  
Quality Requirements ◽  
Research Goal ◽  
Better Than

The nanometric scale researches results can be found, in present, in every industry domains, due to the effects of the new products, obtained on the basis of this researches. In the concrete industry, the research goal at this level is to obtain, finally, a material with new features, whose structural behavior to be considerably better than of the current one. Basically, it aims to achieve, using nanotechnologies, a new structural material for constructions, starting from the current concrete advantages (good compressive strength, durability, etc.), eliminating the disadvantages (low tensile resistance, cracks, etc.), and controlling, in the same time, the costs. Thus, in this paper are presented the required parameters in order to obtain this kind of material, by highlighting the nanocomponents characteristics and the quantities that are used to achieve the expected quality requirements. The real time influence of these nanocomponents on the quality of the studied material can be observed using a dedicated software, specially developed for this purpose.

A-Si:H Solar Cells Deposited Using VHF–PECVD

1996 ◽  
Vol 420 ◽  
Author(s):  
W. G. J. H. M. Van Sark ◽  
J. Bezemer ◽  
R. Van Der Heijden ◽  
W. F. Van Der Weg
Keyword(s):  
Solar Cells ◽  
Chemical Vapour ◽  
Clear Correlation ◽  
Rf Power ◽  
Material Quality ◽  
High Frequencies ◽  
Cell Parameters ◽  
The One ◽  
Very High Frequencies ◽  
Very High

AbstractA-Si:H p+-i-n+ solar cells have been made employing plasma enhanced chemical vapour deposition at frequencies between 30–80 MHz. Here, only the i-layer was fabricated at these very high frequencies (VHF). Both the p+- and n+-layer were made using 13.56 MHz. A previous study has shown the material quality to depend on mainly the applied rf-power, and only slightly on the frequency. It should be noted that for homogeneity reasons a certain optimized pressure is required for each frequency. There is a clear correlation between material quality and solar cell parameters. An initial efficiency of 10 % has been obtained for cells deposited at 65 MHz using a low power density, while the deposition rate still is 2–3 times higher than the one at 13.56 MHz. Light-soaking reveals stabilisation at 6 % for the best cell, which compares well to conventional 13.56 MHz cells.

Effet des paramètres de croissance sur les couches épitaxiales d'InP obtenues par MOCVD (metal-organic chemical vapor deposition) à basse pression

1991 ◽  
Vol 69 (3-4) ◽  
pp. 412-421 ◽  
Author(s):  
P. Cova ◽  
R. A. Masut ◽  
J. F. Currie ◽  
A. Bensaada ◽  
R. Leonelli ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Vapor Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Epitaxial Layers ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

The development of a low pressure, horizontal MOCVD (metal-organic chemical vapour deposition) reactor has allowed us to study the effect of phosphine and trimethylindium molar fluxes on the epitaxial growth of InP. Study of the growth rate in the temperature range 550–620 °C shows that the growth can be limited by the reaction kinetics at the surface. Epitaxial layers of good morphological quality have been obtained by reducing the rate of growth even if the growth is limited by the reaction kinetics at the surface. The variation of the electronic mobility with the PH3 molar flux reveals the existence of an optimum mobility region, even with a constant V: III ratio. Photoluminescence experiments carried out on the samples show the good crystallographic quality of the epitaxial layers. Spectra taken in the energy range 0.8–1.2 eV show the evolution of two structures at 0.91 and 1.08 eV that we associate with an antisite PIn and a VIn defect, respectively.[Journal translation]

scholarly journals Improving the Quality of Friction Stir Welds in Aluminium Alloys

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 539
Author(s):  
Arutiun Ehiasarian ◽  
Yashodhan Purandare ◽  
Arunprabhu Sugumaran ◽  
Papken Hovsepian ◽  
Peter Hatto ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Vapour Deposition ◽  
Aluminium Alloys ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Diamond Like Carbon ◽  
Friction Stir ◽  
Coated Tools ◽  
Arc Evaporation

The Stationary Shoulder Friction Stir Welding (SS-FSW) technique benefits from reduced heat input, improved mechanical properties and surface finish of the weld, avoiding the need for post weld processing. Coatings on the tool probe and the shoulder for welding of aggressive Aluminium alloys have rarely been successful. Such coatings must be well adherent and inert. In this study, coated tools were used for SS-FSW of AA6082-T6 alloy. Performance of a nanoscale multilayer TiAlN/VN coating deposited by High Power Impulse Magnetron Sputtering (HIPIMS) technology was compared with amorphous Diamond Like Carbon (a-C:H) by Plasma Assisted Chemical Vapour Deposition (PACVD), AlTiN deposited by arc evaporation and TiBCN along with TiB2 produced by Chemical Vapour Deposition (CVD) methods. The TiAlN/VN coating was found to have low affinity to aluminium, acceptable coefficient of friction and provided excellent weld quality by inhibiting intermixing between the tool and workpiece materials resulting in a significant reduction in tool wear.

Evaluation of Optical Properties for Nanocrystal Si Dot Layers Fabricated by CVD as a Function of Size Reduction

2012 ◽  
Vol 725 ◽  
pp. 251-254
Author(s):  
Yuki Mizukami ◽  
D. Kosemura ◽  
M. Takei ◽  
Y. Numasawa ◽  
Y. Ohshita ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Optical Properties ◽  
Quantum Confinement ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
X Ray Diffraction ◽  
Confinement Effects ◽  
Quantum Confinement Effects ◽  
Transmission Electron

Raman spectroscopy and photoluminescence were performed in order to understand the optical properties of nanocrystal Si in relation to quantum confinement effects. The nanocrystal Si (nc-Si) dots in the SiO2 layer were fabricated by the H2 plasma treatment and chemical vapour deposition followed by the oxidation of the nc-Si dots surface. The post-annealing was also performed to improve the crystalline quality of nc-Si at 1050 °C for 5 and 10 min. There is a good correlation of the quantum confinement effects between the results of Raman spectroscopy and photoluminescence. The Raman spectra from nc-Si were analysed using the model of Richter et al. As a result, the sizes of the nc-Si dots were consistent with those obtained by transmission electron microscopy and X-ray diffraction. Moreover, the compressive stress in the nc-Si dots were evaluated which was induced by the SiO2 surroundings.

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