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.

Effect of Boron Doping on Microcrystalline Germanium Carbon Thin Films

2007 ◽  
Vol 989 ◽  
Author(s):  
Yasutoshi YASHIKI ◽  
Seiichi KOUKETSU ◽  
Shinsuke MIYAJIMA ◽  
Akira YAMADA ◽  
Makoto KONAGAI
Keyword(s):  
Thin Films ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Boron Doping ◽  
Dark Conductivity ◽  
Hot Wire ◽  
Boron Doped ◽  
Vapor Deposition Technique ◽  
Type C ◽  
P Type

AbstractEffects of boron doping on microcrystalline germanium carbon alloy (μc-Ge1-xCx:H) thin films have been investigated. We deposited boron-doped p-type μc-Ge1-xCx:H thin films by hot-wire chemical vapor deposition technique using hydrogen diluted monomethylgermane (MMG) and diborane (B2H6). A dark conductivity of 1.3 S/cm and carrier concentration of 1.7 x 1020 cm-3 were achieved with B2H6/MMG ratio of 0.1. Furthermore, the activation energy decreased from 0.37 to 0.037 eV with increasing B2H6/MMG ratio from 0 to 0.1. We also fabricated p-type μc-Ge1-xCx:H/n-type c-Si heterojunction diodes. The diodes showed rectifying characteristics. The typical ideality factor and rectifying ratio were 1.4 and 3.7 x 103 at ¡Ó 0.5 V, respectively.

1/f Noise and Thermal Equilibration Effects in Hot Wire Deposited Amorphous Silicon

1996 ◽  
Vol 420 ◽  
Author(s):  
G. M. Khera ◽  
J. Kakalios ◽  
Q. Wang ◽  
E. Iwaniczko
Keyword(s):  
Amorphous Silicon ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Hot Wire ◽  
Thermal Equilibration ◽  
Silicon Thin Films ◽  
Conductance Fluctuations ◽  
Non Gaussian ◽  
Noise Statistics ◽  
Hydrogenated Amorphous

AbstractMeasurements of the conductance fluctuations and thermal equilibration of the dark conductivity of a series of undoped hydrogenated amorphous silicon thin films synthesized by Hot-Wire Chemical Vapor Deposition (HWCVD), with hydrogen contents varying from less than one to twelve atomic percent are reported. The spectral density of the conductance fluctuations varies inversely with frequency f and is dependent upon hydrogen concentration; the 1/f noise statistics are non- Gaussian, indicating correlated fluctuators as is observed in PECVD a-Si:H. These results indicate that aspects of electronic transport and defect dynamics in HWCVD films are similar to those in PECVD a-Si:H films.

Amorphous Silicon Thin-Film Transistors with a Hot-Wire Active-Layer Deposited at High Growth Rate

1997 ◽  
Vol 467 ◽  
Author(s):  
V. Chu ◽  
J. Jarego ◽  
H. Silva ◽  
T. Silva ◽  
M. Boucinha ◽  
...  
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Active Layer ◽  
Thin Film Transistors ◽  
Chemical Vapor ◽  
High Growth ◽  
Dark Conductivity ◽  
High Growth Rate ◽  
Hot Wire ◽  
Silicon Thin Film

ABSTRACTHigh-quality thin film transistors (TFT) with hydrogenated amorphous silicon (a-Si:H) deposited by hot-wire (HW) chemical vapor deposition as the active layer at growth rates above 20 Å/s are compared to TFTs with a-Si:H deposited by RF glow discharge at 1 Å/s. The subgap absorption measured by the constant photocurrent method and steady-state photoconductivity measured between source and drain are used to characterize the a-Si:H in the TFT. The activation energy of the dark conductivity is measured as a function of the gate voltage to obtain the position of the Fermi level. The effect of a bias stress on the TFT transfer curve is obtained.

scholarly journals Synthesis of Boron-Doped Silicon Film Using Hot Wire Chemical Vapor Deposition Technique

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 237
Author(s):  
M. Abul Hossion ◽  
B. M. Arora
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Polycrystalline Silicon ◽  
Silicon Film ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Deposition Technique ◽  
Boron Doped ◽  
Vapor Deposition Technique ◽  
Polycrystalline Silicon Film

Boron-doped polycrystalline silicon film was synthesized using hot wire chemical vapor deposition technique for possible application in photonics devices. To investigate the effect of substrate, we considered Si/SiO2, glass/ITO/TiO2, Al2O3, and nickel tungsten alloy strip for the growth of polycrystalline silicon films. Scanning electron microscopy, optical reflectance, optical transmittance, X-ray diffraction, and I-V measurements were used to characterize the silicon films. The resistivity of the film was 1.3 × 10−2 Ω-cm for the polycrystalline silicon film, which was suitable for using as a window layer in a solar cell. These films have potential uses in making photodiode and photosensing devices.

Hot-Wire Deposited Amorphous Silicon Thin-Film Transistors

1996 ◽  
Vol 424 ◽  
Author(s):  
R. E. I. Schropp ◽  
K. F. Feenstra ◽  
C. H. M. Van Der Werf ◽  
J. Holleman ◽  
H. Meiling
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Thin Film Transistors ◽  
Gate Dielectric ◽  
Chemical Vapor ◽  
Current Crowding ◽  
Hot Wire ◽  
Saturation Regime ◽  
Silicon Thin Film ◽  
Order Of Magnitude

AbstractWe present the first thin film transistors (TFTs) incorporating a low hydrogen content (5 - 9 at.-%) amorphous silicon (a-Si:H) layer deposited by the Hot-Wire Chemical Vapor Deposition (HWCVD) technique. This demonstrates the possibility of utilizing this material in devices. The deposition rate by Hot-Wire CVD is an order of magnitude higher than by Plasma Enhanced CVD. The switching ratio for TFTs based on HWCVD a-Si:H is better than 5 orders of magnitude. The field-effect mobility as determined from the saturation regime of the transfer characteristics is still quite poor. The interface with the gate dielectric needs further optimization. Current crowding effects, however, could be completely eliminated by a H2 plasma treatment of the HW-deposited intrinsic layer. In contrast to the PECVD reference device, the HWCVD device appears to be almost unsensitive to bias voltage stressing. This shows that HW-deposited material might be an approach to much more stable devices.

Amorphous Silicon Selenium Alloy Film Deposited Under Hydrogen Dilution

1991 ◽  
Vol 219 ◽  
Author(s):  
Muzhi He ◽  
Guang H. Lin ◽  
J. O'M. Bockris
Keyword(s):  
Amorphous Silicon ◽  
Chemical Vapor ◽  
Selenium Concentration ◽  
Alloy Film ◽  
Dark Conductivity ◽  
Flow Rate Ratio ◽  
Selenium Atom ◽  
Alloy Films ◽  
Hydrogen Dilution ◽  
Photo Response

ABSTRACTAmorphous silicon selenium alloy films were prepared by plasma enhanced chemical vapor deposition with hydrogen dilution. The flow rate ratio of hydrogen to silane was about 8:1. Amorphous silicon selenium alloy was found to have an optical bandgap ranging from 1.7 eV to 2.0 eV depending on the selenium concentration in the films. The light to dark conductivity ratios of the alloy films are ∼ 104. The optical and electrical properties, Urbach tail energy and sub-bandgap photo response spectroscopy of the alloy film were investigated. The film quality of the alloy deposited with hydrogen dilution is greatly improved comparing to that of the alloy film deposited without hydrogen dilution. The electron spin resonance experiment shows that selenium atom is a good dangling bond terminator.

Deposition of Polysilicon Films by Hot-Wire CVD at Low Temperatures for Photovoltaic Applications

1995 ◽  
Vol 377 ◽  
Author(s):  
J. Puigdollers ◽  
J. Bertomeu ◽  
J. Cifre ◽  
J. Andreu ◽  
J. C. Delgado
Keyword(s):  
Gas Phase ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Amorphous Phases ◽  
Photovoltaic Applications ◽  
Polysilicon Films ◽  
Hydrogen Mixtures ◽  
Si Films ◽  
Substrate Temperatures ◽  
Very High

ABSTRACTPolysilicon (poly-Si) thin films have been obtained using hot-wire chemical vapor deposition (HWCVD) from silane-hydrogen mixtures. The films were prepared at low substrate temperatures (down to 200°C) and at very high deposition rates (up to 40 Å/s). They showed good crystalline properties and no amorphous phases were detected. The films can also be efficiently doped by adding diborane or phosphine to gas phase. In this paper, an overview of the properties of the poly-Si films, intrinsic and p and n-doped, deposited at our laboratory by HWCVD is presented and discussed. The properties of the material and the features of the deposition technique which are interesting for their application in photovoltaics are emphasized.

Large-area Deposition of Amorphous Silicon Alloys Using a Roll-to-roll Operation

2005 ◽  
Vol 870 ◽  
Author(s):  
Subhendu Guha ◽  
Jeffrey Yang
Keyword(s):  
Amorphous Silicon ◽  
Triple Junction ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Chemical Vapor ◽  
Large Area ◽  
Silicon Alloys ◽  
Roll To Roll ◽  
Layer Structures ◽  
Area Deposition

AbstractLarge-area deposition of thin-film amorphous silicon alloy triple-junction solar cells on lightweight and flexible stainless steel substrate is described. The proprietary roll-to-roll operation enables continuous depositions of sophisticated multi-layer structures. The deposition methods include sputtering and plasma-enhanced chemical vapor depositions. Spectrumsplitting triple-junction solar cell design, manufacturing processes, and product applications are presented.

Growth of “New Form” of Polycrystalline Silicon Thin Films Synthesized by Hot Wire Chemical Vapor Deposition

2005 ◽  
Vol 862 ◽  
Author(s):  
A. R. Middya ◽  
J-J. Liang ◽  
K. Ghosh
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Polycrystalline Silicon ◽  
Chemical Vapor ◽  
Crystallographic Structure ◽  
Hot Wire ◽  
Silicon Thin Films ◽  
Vapor Deposition Technique ◽  
New Form

AbstractIn this work, we report on next-generation hot wire chemical vapor deposition technique, we call it ceramics hot-wire CVD. Using a new concept of rectangular ceramics filament holder and “confinement of thermal radiation from the filament”, a “new form” of polycrystalline silicon thin films has been developed at low temperature (˜ 250°C). The grains are found to be symmetrically distributed in array along the parallel lines, in (111) direction. On the surface of individual grains, “five-fold” and “six-fold” symmetries have been observed and we suspect that we developed “buckyball” type “giant silicon molecular solids” with different crystalline silicon lattice other than standard single-crystal silicon structure. We observed rarely found “icosaderal” symmetry in silicon thin films. This hypothesis has been supported by multiple Raman active transverse optical modes and the crystallographic structure analyzed by X-ray diffraction.

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