N-Type Silicon Films Produced by Hot Wire Technique

2000 ◽  
Vol 609 ◽  
Author(s):  
Isabel M. M. Ferreira ◽  
Ana M. F. Cabrita ◽  
Elvira M. C. Fortunato ◽  
Rodrigo F. P. Martins
Keyword(s):  
Pressure Range ◽  
Chemical Vapour ◽  
Dark Conductivity ◽  
Hot Wire ◽  
Large Area ◽  
Deposition Pressure ◽  
Hydrogen Dilution ◽  
Exponential Increase ◽  
Sims Analysis

ABSTRACTThe role of the deposition pressure (p) and the type of filaments (tungsten, W or tantalum, Ta) used to produce large area (10cm×10cm) n-type Si:H films by hot wire chemical vapour (HW-CVD) deposition technique was investigated. The data show that the electro-optical properties of the films produced are dependent on the gas pressure used. In the pressure range of 1×10-3 Torr to 1.0 Torr, the room dark conductivity (σd) varies from 1×10-8 to 2 S/cm for films produced at the same hydrogen dilution and filament temperature (Tfil.). On the other hand, the hydrogen concentration (CH) decreases from 10% to 2%, while the growth rate (R) shows an exponential increase, from 1 to 9 Å/s. The SIMS analysis, within the detection limits, does not reveal the existence of any significant W or Ta contamination in the films produced.

The Effect of Hydrogen Dilution on the Morphology of Carbon Nanowalls Decorated Carbon Nanotubes Deposited by Hot-Wire r.f. Plasma Enhanced Chemical Vapour Deposition

2016 ◽  
Vol 694 ◽  
pp. 203-207
Author(s):  
Nur Maisarah Abdul Rashid ◽  
Wee Siong Chiu ◽  
Noor Hamizah Khanis ◽  
Maisara Othman ◽  
Richard Ritikos ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Hot Wire ◽  
Hydrogen Dilution ◽  
Chemical Vapour Deposition Technique ◽  
Carbon Nanowalls ◽  
Gas Dilution

An investigation on the effects of hydrogen (H2) gas dilution on the morphology and growth of carbon nanowalls (CNWs) decorated carbon nanotubes (CNTs) by hot-wire r.f. plasma enhanced chemical vapour deposition technique is presented. With the assistance of nickel nanoparticle catalyst, CNWs decorated CNTs formed only under the presence of 25% of H2 gas, relative to the methane (CH4) gas precursor. By varying the amount of H2 incorporated with CH4, the role of H2 dilution in the development of CNWs decorated CNTs was studied. Based on the FESEM and HRTEM results, it is hypothesized that H2 density and relative carbon radical concentration are the important parameters for the deposition of CNWs decorated CNTs. The effect of H2 dilution on the formation of CNWs decorated CNTs is presented.

Fast Deposition of Polycrystalline Silicon Films by Hot-Wire CVD

1995 ◽  
Vol 377 ◽  
Author(s):  
A. R. Middya ◽  
A. Lloret ◽  
J. Perrin ◽  
J. Huc ◽  
J. L. Moncel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Polycrystalline Silicon ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Hot Wire ◽  
Crystalline Orientation ◽  
Silicon Thin Films ◽  
Hydrogen Dilution ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTPolycrystalline silicon thin films have been deposited at fast growth rates (50 Å/s) by hotwire chemical vapour deposition (HW-CVD) from SiH4/H2 gas mixtures at low substrate temperature (400–500°C). The surface morphology of these films consists of 0.5 – 2.0μm dendritic grains as seen by electron microscopy. The films have a columnar morphology with grains starting from the substrate either on glass or c-Si. Even the 150 nm thick initial layer is polycrystalline. The preferential crystalline orientation of the poly-Si film is apparently not governed by the radiative source but strongly depends on the type and orientation of the substrate. A strong hydrogen dilution (>90%) of silane is essential to obtain poly-Si films with optimal crystalline structure.

Deposition of High Quality Amorphous Silicon by a New “Hot Wire” CVD Technique

1999 ◽  
Vol 557 ◽  
Author(s):  
Scott Morrison ◽  
Ken Coates ◽  
Jianping Xi ◽  
Arun Madan
Keyword(s):  
Amorphous Silicon ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Hot Wire ◽  
Large Area ◽  
New Approach ◽  
Vapor Deposition Technique ◽  
Photovoltaic Applications ◽  
Technical Issues ◽  
Silicon Materials

AbstractFor the “Hot Wire” chemical vapor deposition technique (HWCVD) method to be applicable for photovoltaic applications, certain critical technical issues need to be addressed and resolved such as: lifetime of the filaments, reproducibility, large area demonstration of the material and stable devices. We have developed a new approach (patent applied for) which addresses some of these problems, specifically longevity of the filaments and reproducibility of the materials produced. The new filament material used has so far shown no appreciable degradation even after deposition of >200 μm of amorphous silicon (a-Si). We report that this can produce “state-ofthe-art” a-Si with a dark conductivity of <10-10 (Ohm*cm)-1 and photoconductivity of >10-5 (Ohm*cm)-1 this material can also be doped p- or n-type. We also provide data using XRD as well as the Raman spectra. These materials have been incorporated into simple Schottky barrier structures. The development of microcrystalline silicon materials is also discussed.

Thermodynamic Model of the Role of Hydrogen Dilution in Plasma Deposition of Microcrystalline Silicon

2001 ◽  
Vol 664 ◽  
Author(s):  
J Robertson
Keyword(s):  
Vapour Deposition ◽  
Plasma Deposition ◽  
Chemical Vapour ◽  
Microcrystalline Silicon ◽  
Surface Mobility ◽  
Hydrogen Dilution ◽  
Surface Nucleation ◽  
Precursor Phase ◽  
Hydrogenated Amorphous

ABSTRACTHydrogen dilution is used to promote the nucleation and growth of microcrystalline Si (μc-Si) by plasma enhanced chemical vapour deposition (PECVD). The free energy of μc-Si and hydrogenated amorphous silicon (a-Si:H) is analysed as a function of Si:H composition in order to derive the effect of hydrogen dilution. It is shown that increasing the hydrogen content of the a-SiHx precursor phase increases the relative stability of μc-Si slightly, but strongly increases the driving force for nucleation. The higher stability of μc-Si is the fundamental origin of the higher etch rates of a-Si:H, while surface mobility models do not account for sub-surface nucleation of μc-Si.

Blue Light Electroluminescence From Doped μc-SiC prepared by Excimer (ArF) Laser Crystallisation

1994 ◽  
Vol 339 ◽  
Author(s):  
S. P. Lau ◽  
J. M. Marshall ◽  
T. E. Dyer ◽  
A. R. Hepburn ◽  
J. F. DaVies
Keyword(s):  
Blue Light ◽  
Light Emission ◽  
Chemical Vapour ◽  
Wide Band ◽  
Dark Conductivity ◽  
Carrier Injection ◽  
Large Area ◽  
Fully Integrated ◽  
Novel Method ◽  
Arf Laser

ABSTRACTA novel method has been developed to prepare highly conductive and wide band gap doped (B2H6/PH3) microcrystalline silicon carbide (μ-SiC) by excimer (ArF) laser crystallisation. Doped a-SiC:H films were prepared by Plasma Enhanced Chemical Vapour Deposition (PECVD), both with and without H2 dilution. After crystallisation, this material has Taue gap of around 2.0 eV and exhibits a dark conductivity as high as 20 (Ωcm)-1, more than ten orders of magnitude higher than before the laser irradiation. This is shown to be mainly due to the formation of SiC microcrystallites in the laser crystallised a-SiC:H.In this paper, we report that this material can be utilised not only as the carrier injection layer in a-SiC:H based Thin Film Light Emitting Diodes (TFLEDs) but also as a luminescent layer. Blue light emission has been observed from a laser crystallised (LC) doped μc-SiC based electroluminescent device, the peak wavelength is around 490nm.The simplicity of excimer (ArF) laser crystallisation and its capability to fabricate poly-Si TFTs, makes this a promising novel method to realise fully integrated Si large area multi-colour displays.

High Quality Microcrystalline Silicon-Carbide Films Prepared by Photo-CVD Method Using Ethylene Gas as a Carbon Source

1999 ◽  
Vol 557 ◽  
Author(s):  
Seung Yeop Myong ◽  
Hyung Kew Lee ◽  
Euisik Yoon ◽  
Koeng Su Lim
Keyword(s):  
Silicon Carbide ◽  
Vapor Deposition ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Microcrystalline Silicon ◽  
Cvd Method ◽  
Hydrogen Dilution ◽  
Boron Doped

AbstractHydrogenated boron-doped microcrystalline silicon-carbide (p-μc-SiC:H) films were grown by a photo chemical vapor deposition (photo-CVD) method from silane (SiH4), hydrogen (H2), diborane (B2H6), and ethylene (C2H4) gases. Since the photo-CVD is a mild process (~10mW/cm2), we can avoid the ion damage of the film, which is inevitable during the deposition of μc-SiC:H employing conventional PECVD technique. A dark conductivity as high as 5 × 10-1 S/cm, together with an optical bandgap of 2 eV, was obtained by the C2H4 addition, which is the first approach in photo-CVD systems. From the Raman and FTIR spectra, it is clear that our p-μc-SiC:H films are made up of crystalline silicon grains embedded in amorphous silicon-carbide tissue. We investigate the role of the hydrogen dilution and ethylene addition on the electrical, optical, and structural properties of p-μc-SiC:H films.

Defects in Microcrystalline Silicon Prepared With Hot Wire CVD

2002 ◽  
Vol 715 ◽  
Author(s):  
F. Finger ◽  
S. Klein ◽  
T. Dylla ◽  
A. L. Baia Neto ◽  
O. Vetterl ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Thin Film Solar Cells ◽  
Hot Wire ◽  
Microcrystalline Silicon ◽  
Grain Sizes ◽  
Preparation Conditions ◽  
Hydrogen Dilution ◽  
Process Gas

AbstractThe influence of the preparation conditions in hot wire chemical vapour deposition (HWCVD) on the electronic properties of microcrystalline silicon is investigated in view of application of the material in thin film solar cells. Poor grain boundary passivation, as a result of hydrogen etching at strong hydrogen dilution of the process gas or thermal desorption of hydrogen at high deposition temperatures, is considered a main obstacle for material optimisation. We conclude that optimum μc-Si:H solar cell material, both from HW-CVD and from plasma enhanced CVD, is not necessarily obtained with largest grain sizes and apparent highest crystalline content, but rather by a material prepared under conditions which yield a compact morphology with an effective grain boundary passivation.

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