VHF Plasma Deposition: A Comparative Overview

1992 ◽  
Vol 258 ◽  
Author(s):  
A. Shah ◽  
J. Dutta ◽  
N. Wyrsch ◽  
K. Prasad ◽  
H. Curtins ◽  
...  
Keyword(s):  
Plasma Deposition ◽  
Chemical Vapour ◽  
High Energy ◽  
High Rate ◽  
Rf Plasma ◽  
Particle Detectors ◽  
Hydrogenated Silicon ◽  
Amorphous Hydrogenated Silicon ◽  
High Energy Tail ◽  
Internal Mechanical Stress

ABSTRACTThe use of plasma excitation frequencies f in the VHF band (30–300 MHz), and particularly of f=70 MHz, for the high-rate deposition of amorphous hydrogenated silicon (a-Si:H) is described. Deposition rates, using monosilane (SiH4) as source gas, are thereby increased roughly five fold to over 10 Å/s as compared with the conventional case of RF plasma enhanced chemical vapour deposition with f=13.56 MHz. This may possibly be attributed to an enhancement in the high-energy tail of the electron energy distribution function (EEDF) of the plasma. Thereby, no noticeable deterioration in film properties is found.Characteristics of VHF-deposited a-Si:H films are extensively reported, including properties like microstructure, hydrogen effusion behaviour and its low internal mechanical stress. High quality hydrogenated microcrystalline silicon (μc-Si:H) can be deposited at low substrate temperature and low plasma power densities thanks to VHF glow discharge. This can be linked to a reduction in sheath potential and to the energy of the ions arriving at the growing surface. Thereafter, use of VHF plasma in applications such as 100 μm thick a-Si:H layer for particle detectors and powder-free deposition of solar cells with efficiencies over 8% are reported.

Amorphous Hydrogenated Silicon Carbide Prepared from DC-Biased RF-Plasma-Enhanced Chemical Vapor Deposition

1991 ◽  
Vol 219 ◽  
Author(s):  
Hsueh Yi Lu ◽  
Mark A. Petrich
Keyword(s):  
Silicon Carbide ◽  
Carbon Content ◽  
Plasma Deposition ◽  
Chemical Vapor ◽  
Plasma Potential ◽  
Rf Plasma ◽  
Hydrogenated Silicon ◽  
Optical Band Gaps ◽  
Amorphous Hydrogenated Silicon ◽  
Dc Bias

ABSTRACTWe present evidence that an independently applied dc bias voltage has a significant effect on the plasma deposition of amorphous hydrogenated silicon carbide. Deposition rates increase with either positive or negative dc voltages applied to the powered rf electrode. The microstructure of the films (as determined by infrared absorption) can be reduced by increasing the plasma potential (positive dc bias voltages). Negative dc biases, or excessively high positive biases, result in increased amounts of film microstructure. Film carbon content is increased when positive biases are applied, but the optical band gaps decrease suggesting increased amounts of graphitic bonding configurations. Negative biases do not change the carbon content of the films, but do increase both deposition rate and microstructure.

Microstructure of Thin Film Photoconductors and its Correlation with Optical and Electronic Properthss

1996 ◽  
Vol 452 ◽  
Author(s):  
U. Klement ◽  
D. Horst ◽  
F. Ernst
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Hydrogenated Silicon ◽  
Amorphous Hydrogenated Silicon ◽  
Transmission Electron ◽  
Electronic Eye

AbstractThe objective of this work is to find a material to replace amorphous hydrogenated silicon used as photosensitive part in the “retina” of an “electronic eye”. For that reason, ZnS, ZnSe, CdS and CdSe were chosen for investigations. Thin films, prepared by chemical vapour deposition, were characterized by transmission electron microscopy. The observed microstructures were correlated with the optoelectronic properties of these materials. CdSe was found to be the most promising material for our application. Hence, the influence of a dielectric interlayer and the effects of additional annealing treatments were analyzed for CdSe and will be discussed with respect to the optimization of the material.

Optical absorption in PECVD deposited thin hydrogenated silicon in light of ordering effects

Open Physics ◽  
2009 ◽  
Vol 7 (2) ◽  
Author(s):  
Jarmila Müllerová ◽  
Veronika Vavruňková ◽  
Pavel Å utta
Keyword(s):  
Chemical Vapour ◽  
Optical Transmittance ◽  
Band Gap Energy ◽  
Absorption Coefficients ◽  
Hydrogenated Silicon ◽  
Transmittance Spectra ◽  
Silicon Thin Films ◽  
Hydrogen Dilution ◽  
Ordering Effects ◽  
Amorphous Hydrogenated Silicon

AbstractWe report results obtained from measurements of optical transmittance spectra carried out on a series of silicon thin films deposited by plasma-enhanced chemical vapour deposition (PECVD) from silane diluted with hydrogen. Hydrogen dilution of silane results in an inhomogeneous growth during which the material evolves from amorphous hydrogenated silicon (a-Si:H) to microcrystalline hydrogenated silicon (µc-Si:H). Spectral refractive indices and absorption coefficients were determined from transmittance spectra. The spectral absorption coefficients were used to determine the Tauc optical band gap energy, the B factor of the Tauc plots, E 04 (energy at which the absorption coefficient is equal to 104 cm−1), and the Urbach energy as a function of the hydrogen dilution. The results were correlated with microstructure, namely volume fractions of the amorphous and crystalline phase with voids, and with the grain size.

High Rate Growth of Amorphous Hydrogenated Silicon Films and their Device Applications

1997 ◽  
Vol 43 (2-3) ◽  
pp. 131-142 ◽  
Author(s):  
Tanay Seth ◽  
C Mukherjee ◽  
C Anandan ◽  
P N Dixit ◽  
O S Panwar ◽  
...  
Keyword(s):  
Silicon Films ◽  
High Rate ◽  
Hydrogenated Silicon ◽  
Amorphous Hydrogenated Silicon ◽  
Device Applications

Micromechanical Behaviour of Amorphous Hydrogenated Silicon Carbide Films

1993 ◽  
Vol 308 ◽  
Author(s):  
J. Meneve ◽  
R. Jacobs ◽  
F. Lostak ◽  
L. Eersels ◽  
E. Dekempeneer ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Chemical Vapour ◽  
Diamond Like Carbon ◽  
Ambient Atmosphere ◽  
Low Friction ◽  
Hydrogenated Silicon ◽  
Amorphous Hydrogenated Silicon ◽  
Low Wear

ABSTRACTAmorphous hydrogenated silicon carbide (a-Si1-xCx:H) films (x = 0.65 to 1) were deposited by radio frequency plasma assisted chemical vapour deposition (RF-PACVD). Their friction and wear properties were investigated by means of a conventional ball-on-disk apparatus. The results were correlated with film mechanical properties. It was found that adding silicon to a-C:H (also called diamond-like carbon (DLC)) films reduces the hardness, elastic modulus and internal stress values by 15 to 30 %. Scratch testing induces film spallation from stainless steel substrates at low loads (1 N). In the low normal load (1 N) ball-on-disk tests under humid N2 conditions, a-Si1-xCx:H films (0.7 < x < 0.9) combine a very low wear rate of both the film and the counterbody with a steady state low friction coefficient below 0.1. For higher loads (5 and 10 N), however, this low friction coefficient only lasts for a relatively short time. In this case, the harder diamond-like carbon films perform tribologically better because of their higher wear resistance, low wear rate of the counterbody and generally low friction coefficients between 0.15 and 0.35 in a humid ambient atmosphere. In a dry N2 atmosphere, pure DLC films perform tribologically better than a-S1-xCx:H films in all respects.

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