scholarly journals Material properties and growth process of microcrystalline silicon with growth rates in excess of 1 nm/s

2001 ◽  
Vol 664 ◽  
Author(s):  
E.A.G. Hamers ◽  
A.H.M. Smets ◽  
C. Smit ◽  
J.P.M. Hoefnagels ◽  
W.M.M. Kessels ◽  
...  
Keyword(s):  
Gas Phase ◽  
Material Properties ◽  
Atomic Hydrogen ◽  
Growth Process ◽  
Dark Conductivity ◽  
Microcrystalline Silicon ◽  
Hydrogen Flux ◽  
Typical Material ◽  
Crystallite Sizes ◽  
20 Nm

ABSTRACTThe expanding thermal plasma (ETP) has been used to deposit microcrystalline silicon (µc-Si:H) with rates up to 2.7 nm/s. Typical material properties of well crystallised material are crystallite sizes of 20 nm, photo- and dark conductivity of 2×10−5 and 2x10−7 S/cm respectively, and an activation energy of 600 meV. The radical densities of SiH3, SiH, and Si present in the gas phase have been quantified. In conditions where [.proportional µc-Si:H is deposited the atomic hydrogen flux towards the surface is of the same magnitude or higher as the flux of deposited radicals. Furthermore, the abundance of radicals such as SiH and Si is large and may contribute several tens of percent to the deposition rate.

Nucleation and Growth in Vicinity of Growing Surface in Making Microcrystalline Silicon

1990 ◽  
Vol 192 ◽  
Author(s):  
Masami Nakata ◽  
Tatsuru Namikawa ◽  
Hajime Shirai ◽  
Jun-ichi Hanna ◽  
Isamu Shimizu
Keyword(s):  
Substrate Temperature ◽  
Gas Phase ◽  
Atomic Hydrogen ◽  
Nucleation And Growth ◽  
Microcrystalline Silicon ◽  
Gas Phase Reactions ◽  
Plasma Enhanced Cvd ◽  
Close Study

ABSTRACTA close study was conducted on microcrystalline Silicon (μc-Si) prepared by PE-CVD (Plasma Enhanced CVD) from SiF4 with the assistance of atomic hydrogen. The atomic hydrogen played a major role in either making precursors, SiFnHm (n+m=3), by gas phase reactions with the fragments, SiFn (≤3), or constructing Si-network in the vicinity of the growing surface. Proper conditions of nucleation were markedly different from those of growth with respect to parameters, flow of atomic hydrogen and substrate temperature.

scholarly journals The atomic hydrogen flux during microcrystalline silicon solar cell deposition

2008 ◽  
Author(s):  
M.C.M. van de Sanden ◽  
G. Dingemans ◽  
M. N. van den Donker ◽  
D. Hrunski ◽  
A. Gordijn ◽  
...  
Keyword(s):  
Solar Cell ◽  
Atomic Hydrogen ◽  
Silicon Solar Cell ◽  
Microcrystalline Silicon ◽  
Hydrogen Flux

scholarly journals The atomic hydrogen flux to silicon growth flux ratio during microcrystalline silicon solar cell deposition

2008 ◽  
Vol 93 (11) ◽  
pp. 111914 ◽  
Author(s):  
G. Dingemans ◽  
M. N. van den Donker ◽  
D. Hrunski ◽  
A. Gordijn ◽  
W. M. M. Kessels ◽  
...  
Keyword(s):  
Solar Cell ◽  
Atomic Hydrogen ◽  
Silicon Solar Cell ◽  
Flux Ratio ◽  
Microcrystalline Silicon ◽  
Hydrogen Flux ◽  
Silicon Growth

Transport Path in Hydrogenated Microcrystalline Silicon

2002 ◽  
Vol 715 ◽  
Author(s):  
N. Wyrsch ◽  
C. Droz ◽  
L. Feitknecht ◽  
J. Spitznagel ◽  
A. Shah
Keyword(s):  
Raman Spectroscopy ◽  
Volume Fraction ◽  
Conductivity Measurement ◽  
Dark Conductivity ◽  
Transition Regime ◽  
Conductivity Data ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Crystalline Fraction ◽  
Transport Path

AbstractUndoped microcrystalline silicon samples deposited in the transition regime between amorphous and microcrystalline growth have been investigated by dark conductivity measurement and Raman spectroscopy. From the latter, a semi-quantitative crystalline volume fraction Xc of the sample was deduced and correlated with dark conductivity data in order to reveal possible percolation controlled transport. No threshold was observed around the critical crystalline fraction value Xc of 33%, as reported previously, but a threshold in conductivity data was found at Xc≈50%. This threshold is interpreted here speculatively as being the result of postoxidation, and not constituting an actual percolation threshold.

High Temperature n- and p-type Doped Microcrystalline Silicon Layers Grown by VHF PECVD Layer-by-Layer Deposition

2003 ◽  
Vol 762 ◽  
Author(s):  
A. Gordijn ◽  
J.K. Rath ◽  
R.E.I. Schropp
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
High Temperatures ◽  
Continuous Wave ◽  
Hydrogen Plasma ◽  
Silicon Layer ◽  
Dark Conductivity ◽  
High Deposition Rate ◽  
Layer By Layer ◽  
Microcrystalline Silicon

AbstractDue to the high temperatures used for high deposition rate microcrystalline (μc-Si:H) and polycrystalline silicon, there is a need for compact and temperature-stable doped layers. In this study we report on films grown by the layer-by-layer method (LbL) using VHF PECVD. Growth of an amorphous silicon layer is alternated by a hydrogen plasma treatment. In LbL, the surface reactions are separated time-wise from the nucleation in the bulk. We observed that it is possible to incorporate dopant atoms in the layer, without disturbing the nucleation. Even at high substrate temperatures (up to 400°C) doped layers can be made microcrystalline. At these temperatures, in the continuous wave case, crystallinity is hindered, which is generally attributed to the out-diffusion of hydrogen from the surface and the presence of impurities (dopants).We observe that the parameter window for the treatment time for p-layers is smaller compared to n-layers. Moreover we observe that for high temperatures, the nucleation of p-layers is more adversely affected than for n-layers. Thin, doped layers have been structurally, optically and electrically characterized. The best n-layer made at 400°C, with a thickness of only 31 nm, had an activation energy of 0.056 eV and a dark conductivity of 2.7 S/cm, while the best p-layer made at 350°C, with a thickness of 29 nm, had an activation energy of 0.11 V and a dark conductivity of 0.1 S/cm. The suitability of these high temperature n-layers has been demonstrated in an n-i-p microcrystalline silicon solar cell with an unoptimized μc-Si:H i-layer deposited at 250°C and without buffer. The Voc of the cell is 0.48 V and the fill factor is 70 %.

Nanozirconium Carbide Powder Synthesis via Carbothermal Route

2013 ◽  
Vol 334-335 ◽  
pp. 381-386 ◽  
Author(s):  
F. Arianpour ◽  
F. Kazemi ◽  
Hamid Reza Rezaie ◽  
A. Asjodi ◽  
J. Liu
Keyword(s):  
Carbon Sources ◽  
Zirconium Carbide ◽  
Carbide Powder ◽  
Carbide Formation ◽  
Matrix Composites ◽  
Powder Synthesis ◽  
High Refractoriness ◽  
Heat Treated ◽  
Crystallite Sizes ◽  
20 Nm

Zirconium carbide (ZrC) has extended application in many ceramic and metal matrix composites especially used for ultra high temperature conditions. The synthesis of zirconium carbide powder is costly and difficult because of its high refractoriness and chemically inert properties. In this research, the synthesis of zirconium carbide nanopowder at low temperature via carbothermal reduction route was investigated according to thermodynamic data. The starting materials were zirconium acetate and sucrose as zirconium and carbon sources, respectively. After preparation of different carbon/zirconium ratio containing precursors, the dried precursors were heat treated at 1400°C and vacuum atmosphere. Also the ZrC formation was followed by thermal analysis of the produced precursors. The phase evolutions and microstructural studies were carried out using X-ray diffraction and scanning electron microscopy. The results showed that it is possible to synthesis zirconium carbide nanopowder with round shape and crystallite sizes smaller than 20 nm at low temperatures. Also according to thermodynamic calculations, it was concluded that by applying vacuum condition, the zirconium carbide formation can occur at less than 1000°C which is very effective on the size reducing of produced ZrC nanopowders.

Gas Phase Atomic Hydrogen-Induced Hydrogenation of Cyclohexene on the Ni(100) Surface

1997 ◽  
Vol 101 (18) ◽  
pp. 3540-3546 ◽  
Author(s):  
Kyung-Ah Son ◽  
John L. Gland
Keyword(s):  
Gas Phase ◽  
Atomic Hydrogen

Intrinsic and Doped m c-Si:H TFT Layers using 13.56 MHz PECVD at 250°C

2004 ◽  
Vol 808 ◽  
Author(s):  
Czang-Ho Lee ◽  
Denis Striakhilev ◽  
Arokia Nathan
Keyword(s):  
Performance Improvement ◽  
Volume Fraction ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Rf Power ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Bias Stress ◽  
Hydrogen Dilution ◽  
Low Threshold

ABSTRACTUndoped and n+ hydrogenated microcrystalline silicon (μc-Si:H) films for thin film transistors (TFTs) were deposited at a temperature of 250°C with 99 ∼ 99.6 % hydrogen dilution of silane by standard 13.56 MHz plasma enhanced chemical vapor deposition (PECVD). High crystallinity m c-Si:H films were achieved at 99.6 % hydrogen dilution and at low rf power. An undoped 80 nm thick m c-Si:H film showed a dark conductivity of the order of 10−7 S/cm, the photosensitivity of an order of 102, and a crystalline volume fraction of 80 %. However, a 60 nm thick n+ μc-Si:H film deposited using a seed layer showed a high dark conductivity of 35 S/cm and a crystalline volume fraction of 60 %. Using n+ μc-Si:H films as drain and source contact layers in a-Si:H TFTs provides substantial performance improvement over n+ a-Si:H contacts. Finally, fully μ c-Si:H TFTs incorporating intrinsic m c-Si:H films as channel layers and n+ μc-Si:H films as contact layers have been fabricated and characterized. These TFTs exhibit a low threshold voltage and a field effect mobility of 0.85 cm2/Vs, and are far more stable under gate bias stress than a-Si:H TFTs.

Absorption of gas-phase atomic hydrogen by Si(100): Effect of surface atomic structures

2001 ◽  
Vol 79 (1) ◽  
pp. 36-38 ◽  
Author(s):  
Jae Yeol Maeng ◽  
Sehun Kim ◽  
S. K. Jo ◽  
W. P. Fitts ◽  
J. M. White
Keyword(s):  
Gas Phase ◽  
Atomic Hydrogen ◽  
Atomic Structures ◽  
Effect Of Surface
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