Experimental Study of Silane Plasma Nanoparticle Formation in Amorphous Silicon Thin Films

2005 ◽  
Vol 862 ◽  
Author(s):  
S. Thompson ◽  
C. R. Perrey ◽  
T. J. Belich ◽  
C. Blackwell ◽  
C. B. Carter ◽  
...  

AbstractRF glow discharge deposited hydrogenated amorphous silicon films containing silicon nanocrystalline inclusions (a/nc-Si:H) films are investigated as a function of a thermal gradient applied across the silane plasma during film growth. The a/nc-Si:H films are synthesized from hydrogen-diluted silane plasmas when a capacitively-coupled plasma enhanced chemical vapor deposition reactor is operated at high gas chamber pressures. Plasma diagnostics and transmission electron microscopy image analysis of films deposited with and without a thermal gradient suggest that nanoparticle formation occurs within the plasma, rather than resulting from solid-state nucleation at the growing film surface.

2006 ◽  
Vol 910 ◽  
Author(s):  
C. Anderson ◽  
C. Blackwell ◽  
J. Deneen ◽  
C. B. Carter ◽  
James Kakalios ◽  
...  

AbstractThe production of hydrogenated amorphous silicon films containing silicon nanocrystal-line inclusions (a/nc-Si:H) is demonstrated using a new deposition process. Crystalline Si nanoparticles around 5 nm in diameter are generated in a flow-through plasma reactor, and are introduced into a downstream capacitively-coupled plasma enhanced chemical vapor deposition reactor where the particles are “co-deposited” with the amorphous phase of the film. Transmis-sion electron microscopy confirms the presence of crystalline inclusions in these films, as well as providing confirmation that the crystalline particles are indeed produced in the flow-through re-actor and not in the capacitive plasma. Electrical measurements indicate an improvement in the dark conductivity of the intrinsic a/nc-Si:H films as the particle concentration is increased, sug-gesting that the particles have a doping effect on the films charge transport properties.


1994 ◽  
Vol 345 ◽  
Author(s):  
T. Kretz ◽  
D. Pribat ◽  
P. Legagneux ◽  
F. Plais ◽  
O. Huet ◽  
...  

AbstractHigh purity amorphous silicon layers were obtained by ultrahigh vacuum (millitorr range) chemical vapor deposition (UHVCVD) from disilane gas. The crystalline fraction of the films was monitored by in situ electrical conductance measurements performed during isothermal annealings. The experimental conductance curves were fitted with an analytical expression, from which the characteristic crystallisation time, tc, was extracted. Using the activation energy for the growth rate extracted from our previous work, we were able to determine the activation energy for the nucleation rate for the analysed-films. For the films including small crystallites we have obtained En ∼ 2.8 eV, compared to En ∼ 3.7 eV for the completely amorphous ones.


2011 ◽  
Vol 383-390 ◽  
pp. 6980-6985
Author(s):  
Mao Yang Wu ◽  
Wei Li ◽  
Jun Wei Fu ◽  
Yi Jiao Qiu ◽  
Ya Dong Jiang

Hydrogenated amorphous silicon (a-Si:H) thin films doped with both Phosphor and Nitrogen are deposited by ratio frequency plasma enhanced chemical vapor deposition (PECVD). The effect of gas flow rate of ammonia (FrNH3) on the composition, microstructure and optical properties of the films has been investigated by X-ray photoelectron spectroscopy, Raman spectroscopy and ellipsometric spectra, respectively. The results show that with the increase of FrNH3, Si-N bonds appear while the short-range order deteriorate in the films. Besides, the optical properties of N-doped n-type a-Si:H thin films can be easily controlled in a PECVD system.


2007 ◽  
Vol 124-126 ◽  
pp. 1063-1066 ◽  
Author(s):  
Jin O Song ◽  
Heung Taek Shim ◽  
Dong Jin Byun ◽  
Joong Kee Lee

Effects of substrate temperature and phosphor doping on electrochemical characteristics of the silicon film anode were investigated. The silicon thin films were synthesized directly on copper foil by radio-frequency capacitively coupled plasma-enhanced chemical-vapor deposition (r.f.-CVD). The cyclability of the silicon anode greatly depends on the surface morphology and surface resistivity. The silicon film anodes which have granular structure and high conductivity showed higher cyclabilty than those of planer and low conductivity, respectively.


2007 ◽  
Vol 989 ◽  
Author(s):  
Xiao Liu ◽  
Thomas H Metcalf ◽  
Qi Wang ◽  
Douglas M Photiadis

AbstractWe have measured the internal friction (Q-1) of amorphous silicon nitride (a-Si3Nx) films prepared by a variety of methods, including low-pressure chemical-vapor deposition (LPCVD), plasma-enhanced chemical-vapor deposition (PECVD), and hot-wire chemical-vapor deposition (HWCVD) from 0.5 K to room temperature. The measurements are made by depositing the films onto extremely high-Q silicon double paddle oscillator substrates with a resonant frequency of ~5500 Hz. We find the elastic properties of these a-Si3N4 films resemble those of amorphous silicon (a-Si), demonstrating considerable variation, depending on the film growth methods and post deposition annealing. The internal friction for most of the films shows a broad temperature-independent plateau below 30 K, characteristic of amorphous solids. The values of Q-1, however, vary from film to film in this plateau region by more than one order of magnitude. This is typical for tetrehedrally bonded amorphous thin films, like a-Si, a-Ge, and a-C. The PECVD films have the highest Q-1 just like an ordinary amorphous solid, while LPCVD films have an internal friction more than one order of magnitude lower. All the films show a reduction of Q-1 after annealing at 800°C, even for the LPCVD films which were prepared at 850°C. This can be viewed as a reduction of structural disorder.


1997 ◽  
Vol 467 ◽  
Author(s):  
G. Viera ◽  
P. Roca i Cabarrocas ◽  
S. Hamma ◽  
S. N. Sharma ◽  
J. Costa ◽  
...  

ABSTRACTNanostructured silicon thin films have been deposited by plasma enhanced chemical vapor deposition at low substrate temperature (100 °C) in the presence of silicon nanoparticles. The nanostructure of the films was revealed by transmission electron microscopy, Raman spectroscopy and X-ray diffraction, which showed ordered silicon domains (1–2 nm) embedded in an amorphous silicon matrix. These ordered domains are due to the particles created in the discharge that contribute to the film growth. One consequence of the incorporation of nanoparticles is the accelerated crystallization of the nanostructured silicon thin films when compared to standard a-Si:H, as shown by the electrical characterization during the annealing.


1998 ◽  
Vol 13 (9) ◽  
pp. 2476-2479 ◽  
Author(s):  
E. Bertran ◽  
S. N. Sharma ◽  
G. Viera ◽  
J. Costa ◽  
P. St'ahel ◽  
...  

Thin films of nanostructured silicon (ns-Si:H) were deposited by plasma-enhanced chemical vapor deposition in the presence of silicon nanoparticles at 100 °C substrate temperature using a silane and hydrogen gas mixture under continuous wave (cw) plasma conditions. The nanostructure of the films has been demonstrated by diverse ways: transmission electron microscopy, Raman spectroscopy, and x-ray diffraction, which have shown the presence of ordered silicon clusters (1–2 nm) embedded in an amorphous silicon matrix. Because of the presence of these ordered domains, the films crystallize faster than standard hydrogenated amorphous silicon samples, as evidenced by electrical measurements during the thermal annealing.


1989 ◽  
Vol 149 ◽  
Author(s):  
S. A. Cruz-Jimenez ◽  
S. Muhl ◽  
R. Salcedo

Plasma Enhanced Chemical Vapor Deposition CPECVD) is used extensively for the preparation of amorphous materials. However, to date we do not have a full description of the deposition process. By this we refer to the following steps ; the source gas decomposition [1], the gas phase reactions, diffusion within the plasma [a], adsorption of the various species, solid-gas reactions, nucleation and subsequent film growth [3–7]. To a large extent the diversity of the processes which are involved in film formation explain the observed variation in the characteristics of supposedly identical material made in different laboratories. Even with such variations certain trends relating the properties of the materials with the growth processes are apparent. In particular it is well established that hydrogen saturation of the dangling bonds is essential. Although how much hydrogen is optimum, and how it is incorporated in the growing film are questions of considerable importance.


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