Stress and Crystallization of Plasma Enhanced Chemical Vapour Deposition Nanocrystalline Silicon Films

2008 ◽  
Vol 8 (5) ◽  
pp. 2693-2698 ◽  
Author(s):  
S. B. Milne ◽  
Y. Q. Fu ◽  
J. K. Luo ◽  
A. J. Flewitt ◽  
S. Pisana ◽  
...  
Keyword(s):  
Film Growth ◽  
Chemical Vapour ◽  
Nanocrystalline Silicon ◽  
Film Structure ◽  
Intrinsic Stress ◽  
Plasma Power ◽  
Annealing Conditions ◽  
Si Films ◽  
Gas Ratio ◽  
Nanocrystalline Si

Nanocrystalline Si films were prepared with a RF-PECVD system using different SiH4/H2 ratios, plasma powers, substrate temperatures and annealing conditions. The film's intrinsic stress was characterized in relation to the crystallization fraction. Results show that an increasing H2 gas ratio, plasma power or substrate temperature can shift the growth mechanism across a transition point, past which nanocrystalline Si is dominant in the film structure. The film's intrinsic stress normally peaks during this transition region. Different mechanisms of stress formation and relaxation during film growth were discussed, including ion bombardment effects, hydrogen induced bond-reconstruction and nanocomposite effects (nanocrystals embedded in an amorphous Si matrix). A three-parameter schematic plot has been proposed which is based on the results obtained. The film structure and stress are presented in relation to SiH4 gas ratio, plasma power and temperature.

scholarly journals The structural characterisation of HWCVD-deposited nanocrystalline silicon films

2009 ◽  
Vol 105 (1/2) ◽  
Author(s):  
Bibhu P. Swain
Keyword(s):  
Vapour Deposition ◽  
Chemical Vapour ◽  
Nanocrystalline Silicon ◽  
X Ray Diffraction ◽  
Crystalline Fraction ◽  
X Ray ◽  
Structural Characterisation ◽  
X Ray Scattering ◽  
Si Films ◽  
Guinier Plot

Nanocrystalline silicon (nc-Si) films were deposited by hot-wire chemical vapour deposition (HWCVD) in the presence of varying H2 concentrations and their structural and interfacial character investigated by X-ray diffraction, small-angle X-ray scattering (SAXS) and Raman spectroscopy. The crystalline fraction was around 30–50% and the nc-Si crystallite size was in the range 20–35 nm. The SAXS results were analysed by Guinier plot, scaling factor, and correlation distance. The nc-Si grains displayed a mass fractal appearance, and the interfacial inhomogeneity distance was ~2 nm.

THE SIZE CONTROL OF UNIFORM NANOCRYSTALLINE Si GRAINS BY CONSTRAINED GROWTH MODEL

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2751-2756 ◽  
Author(s):  
KUNJI CHEN ◽  
KAI CHEN ◽  
PEIGAO HAN ◽  
HECHENG ZOU ◽  
ZHONGYUAN MA ◽  
...  
Keyword(s):  
Size Control ◽  
Nanocrystalline Silicon ◽  
Annealing Conditions ◽  
Crystallization Method ◽  
Transmission Electron ◽  
Mean Size ◽  
Sublayer Thickness ◽  
The Mean ◽  
Size Controlled ◽  
Nanocrystalline Si

Size-controlled nanocrystalline silicon ( nc - Si ) has been prepared from a - SiN x / a - Si:H/a - SiN x ( 'a' standing for amorphous) sandwich structures by thermal annealing. Transmission electron microscope analyses show that the mean size and the grain size distribution (GSD) of the nc - Si are controlled by the annealing conditions and the a - Si sublayer thickness. Based on our theoretical model of constrained crystallization, we interpret the phenomena of the growth halt of nc - Si and higher crystallization temperature for the thinner a - Si sublayers. The experimental results show that constrained crystallization method is promising to achieve uniform and high density nc - Si array which can be used in the future nano-devices.

Low Temperature Growth of Nanocrystalline Silicon From SiF4 + SiH4

1996 ◽  
Vol 424 ◽  
Author(s):  
Yu Chen ◽  
M. Taguchi ◽  
S. Wagner
Keyword(s):  
Electrical Conductivity ◽  
Low Temperature ◽  
Strong Influence ◽  
Nanocrystalline Silicon ◽  
Film Structure ◽  
Constant Thickness ◽  
Temperature Growth ◽  
Low Temperature Growth ◽  
Arsenic Doping ◽  
Si Films

AbstractThe electrical conductivity of nc-Si films grown from SiF4 and H2 with constant arsenic doping rises from 10-5 to 10 Scm-1 as the thickness rises from ˜ 0.1 to 1 μm. This variation demonstrates the strong influence of film structure on conductivity. We show that the conductivity of undoped nc-Si films of constant thickness can be varied by adding SiH4 to the SiF4 and H2 source gas.

Oxidation Reduction in Nanocrystalline Silicon Grown by Hydrogen-Profiling Technique

2016 ◽  
Vol 41 ◽  
pp. 9-17 ◽  
Author(s):  
Christopher J. Arendse ◽  
Theophillus F.G. Muller ◽  
Franscious R. Cummings ◽  
Clive J. Oliphant
Keyword(s):  
Amorphous Silicon ◽  
Hydrogen Concentration ◽  
Film Growth ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Chemical Vapour ◽  
Silicon Layer ◽  
Nanocrystalline Silicon ◽  
Substrate Interface ◽  
Nano Crystalline

The deposition of a compact amorphous silicon/nano-crystalline silicon material is demonstrated by hot-wire chemical vapour deposition using a sequential hydrogen profiling technique at low hydrogen dilutions. Nano-crystallite nucleation occurs at the substrate interface that develops into a uniform, porous crystalline structure as the growth progresses. A further reduction in the H-dilution results in the onset of a dense amorphous silicon layer. The average crystalline volume fraction and nano-crystallite size in the sample bulk amounts to 30% and 6 nm, respectively, as probed by Raman spectroscopy using the 647 nm excitation. The change in hydrogen dilution is accompanied by a graded hydrogen concentration depth-profile, where the hydrogen concentration decreases as the growth progresses. The level of post-deposition oxidation is considerably reduced, as inferred from infrared spectroscopy. The presence of oxygen is mainly confined to the substrate interface as a result of thermal oxidation during thin film growth.

Injection Electroluminescence from Thin Film p-i-n Structures made from Nanocrystalline Hydrogenated Silicon

1996 ◽  
Vol 452 ◽  
Author(s):  
A. A. Andreev ◽  
B. Y. Averbouch ◽  
P. Mavlyanov ◽  
S. B. Aldabergenova ◽  
M. Albrecht ◽  
...  
Keyword(s):  
Amorphous Matrix ◽  
Volume Fraction ◽  
Interband Transition ◽  
Stokes Shift ◽  
Chemical Vapour ◽  
Nanocrystalline Silicon ◽  
Film Structure ◽  
High Hydrogen ◽  
Fast Kinetics ◽  
Deposition Parameter

AbstractNanocrystalline silicon films are prepared by plasma enhanced chemical vapour deposition of silane under the conditions of high hydrogen dilution (3:100). The film structure consists of nanoclusters 0.8 to 5 nm in size (volume fraction 30%) embedded in an amorphous matrix. The Taue gap of the amorphous matrix is 1.95 to 2.05 eV depending on deposition parameter. These films are characterized as regards photoluminescence (PL) and, prepared to p-i-n structures, electroluminescence (EL). The PL and EL agree in (i) luminescence peak at 1.9 eV, i.e. small Stokes shift, (ii) almost no temperature dependence between 77 K and 293 K, (iii) fast kinetics with time constant of a few 10−8 s. These data can be understood in terms of quantum confinement in Si nanocrystallites smaller than around 2 nm. The EL in addition exhibits a luminescence band extending up to 3 eV, which can be interpreted by interband transition due the hot carriers.

Nanocrystalline silicon ( nc-Si ) from single ion beam sputtering

2003 ◽  
Vol 762 ◽  
Author(s):  
Z.B. Zhou ◽  
G.M. Hadi ◽  
R.Q. Cui ◽  
Z.M. Ding ◽  
G. Li
Keyword(s):  
Solar Cell ◽  
Ion Beam ◽  
Nanocrystalline Silicon ◽  
Silicon Films ◽  
Chamber Pressure ◽  
Ion Beam Sputtering ◽  
High Hydrogen ◽  
Beam Sputtering ◽  
Si Films ◽  
Nanocrystalline Silicon Films

AbstractBased on a small set of selected publications on the using of nanocrystalline silicon films (nc-Si) for solar cell from 1997 to 2001, this paper reviews the application of nc-Si films as intrinsic layers in p-i-n solar cells. The new structure of nc-Si films deposited at high chamber pressure and high hydrogen dilution have characters of nanocrystalline grains with dimension about several tens of nanometer embedded in matrix of amorphous tissue and a high volume fraction of crystallinity (60~80%). The new nc-Si material have optical gap of 1.89 eV. The efficiency of this single junction solar cell reaches 8.7%. This nc-Si layer can be used not only as an intrinsic layer and as a p-type layer. Also nanocrystalline layer may be used as a seed layer for the growth of polycrystalline Si films at a low temperature.We used single ion beam sputtering methods to synthesize nanocrystalline silicon films successfully. The films were characterized with the technique of X-ray diffraction, Atomic Force Micrographs. We found that the films had a character of nc-amorphous double phase structure. Conductivity test at different temperatures presented the transportation of electrons dominated by different mechanism within different temperature ranges. Photoconductivity gains of the material were obtained in our recent investigation.

scholarly journals Light Emission from Rare-Earth Doped Silicon Nanostructures

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
J. Li ◽  
O. H. Y. Zalloum ◽  
T. Roschuk ◽  
C. L. Heng ◽  
J. Wojcik ◽  
...  
Keyword(s):  
Rare Earth ◽  
Electron Cyclotron Resonance ◽  
Light Emission ◽  
Chemical Vapour ◽  
Annealing Conditions ◽  
Lighting Conditions ◽  
Deposition Parameters ◽  
Doped Silicon ◽  
Rare Earth Doped ◽  
Resonance Plasma

Rare earth (Tb or Ce)-doped silicon oxides were deposited by electron cyclotron resonance plasma-enhanced chemical vapour deposition (ECR-PECVD). Silicon nanocrystals (Si-ncs) were formed in the silicon-rich films during certain annealing processes. Photoluminescence (PL) properties of the films were found to be highly dependent on the deposition parameters and annealing conditions. We propose that the presence of a novel sensitizer in the Tb-doped oxygen-rich films is responsible for the indirect excitation of the Tb emission, while in the Tb-doped silicon-rich films the Tb emission is excited by the Si-ncs through an exciton-mediated energy transfer. In the Ce-doped oxygen-rich films, an abrupt increase of the Ce emission intensity was observed after annealing at 1200∘C. This effect is tentatively attributed to the formation of Ce silicate. In the Ce-doped silicon-rich films, the Ce emission was absent at annealing temperatures lower than 1100∘C due to the strong absorption of Si-ncs. Optimal film compositions and annealing conditions for maximizing the PL intensities of the rare earths in the films have been determined. The light emissions from these films were very bright and can be easily observed even under room lighting conditions.

Optimization of p-type Nanocrystalline Silicon Thin Films for Solar Cells and Photodiodes

2009 ◽  
Vol 1153 ◽  
Author(s):  
Yuri Vygranenko ◽  
Ehsanollah Fathi ◽  
Andrei Sazonov ◽  
Manuela Vieira ◽  
Gregory Heiler ◽  
...  
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Chemical Vapor ◽  
Percolation Cluster ◽  
Nanocrystalline Silicon ◽  
Film Structure ◽  
Silicon Thin Films ◽  
Low Leakage ◽  
In Doping ◽  
P Type

AbstractWe report on structural, electronic, and optical properties of boron-doped, hydrogenated nanocrystalline silicon (nc-Si:H) thin films deposited by plasma-enhanced chemical vapor deposition (PECVD) at a substrate temperature of 150°C. Film properties were studied as a function of trimethylboron-to-silane ratio and film thickness. The film thickness was varied in the range from 14 to 100 nm. The conductivity of 60 nm thick films reached a peak value of 0.07 S/cm at a doping ratio of 1%. As a result of amorphization of the film structure, which was indicated by Raman spectra measurements, any further increase in doping reduced conductivity. We also observed an abrupt increase in conductivity with increasing film thickness ascribed to a percolation cluster composed of silicon nanocrystallites. The absorption loss of 25% at a wavelength of 400 nm was measured for the films with optimized conductivity deposited on glass and glass/ZnO:Al substrates. A low-leakage, blue-enhanced p-i-n photodiode with an nc-Si p-layer was also fabricated and characterized.

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