The Influence of W Filament Alloying on the Electronic Properties of Hwcvd Deposited a-Si:H Films

2000 ◽  
Vol 609 ◽  
Author(s):  
A. H. Mahan ◽  
A. Mason ◽  
B. P. Nelson ◽  
A. C. Gallagher
Keyword(s):  
Electronic Properties ◽  
Diffusion Length ◽  
Depth Profiling ◽  
Film Surface ◽  
Film Deposition ◽  
Alloy Formation ◽  
Central Regions ◽  
Film Deposition Rate ◽  
Filament Surface ◽  
Post Deposition

ABSTRACTIn depositing a-Si:H by HWCVD using W filaments, one issue common to this technique is that of filament lifetime. When using undiluted silane as the source gas, a buildup of silicon at the colder ends of the filament is routinely observed (thickening), and it is here that filament breakage usually occurs. Less well understood is the effect of filament alloy formation on a-Si:H electronic properties. In this work we combine ambipolar diffusion length (SSPG) measurements on consecutively deposited a-Si:H films with SEM surface topography and sputter (SP) Auger depth profiling of the filament Si/(W+Si) composition to track film electronic properties as a function of the Si buildup on short filaments entirely exposed to the growing film surface. We find that with increasing exposure time of the filament to silane, appreciable Si exists everywhere along the filament length, even in the non-thickened central regions. We discuss the effect of this alloying on the film deposition rate and electronic properties, and suggest that the nature of the filament surface must be carefully considered when optimizing a- Si:H film electronic properties. Finally, we discuss possible ways to minimize this alloying by post deposition treatments, which include different filament ‘run’ temperatures.

Phononic Amorphous Silicon: Theory, Material, and Devices

2006 ◽  
Vol 910 ◽  
Author(s):  
Samrat Chawda ◽  
Jose Mawyin ◽  
Harv Mahan ◽  
Charles Fortmann ◽  
Gary Halada
Keyword(s):  
Amorphous Silicon ◽  
Diffusion Length ◽  
Phonon Scattering ◽  
Crystalline Silicon ◽  
Film Deposition ◽  
Fully Integrated ◽  
Phonon Spectra ◽  
Experimental Approaches ◽  
Post Deposition ◽  
Limited Diffusion

AbstractThe field of phononic-engineered amorphous silicon is introduced. Specifically the construction of devices and waveguides for information conveyance and manipulation via phonons are considered. Typically the phononic properties of a given material are immutable and the phonons have such a limited diffusion length (nanometers) as to be unsuitable for engineering purposes. Crystalline silicon on the other hand has a reasonably large thermal conductivity and phonon diffusion length at sufficiently low temperatures. Phonon diffusion lengths can measure up to centimeters (e.g., crystalline SiO2) at temperature less than 10K but drop to sub microns at room temperature. Amorphous silicon, owing to the inherent scattering structures and owing to localization (of at least some phonon bands), has an anomalously large phonon lifetime [1]. This lifetime maybe indicative of a large phonon diffusion length and/or a fast phonon hop rate from one domain to the next and/or an indication that more than the typical three phonons (umklapp process) are involved in phonon scattering (e.g., see [1]&[2]). Techniques involving small-scaled devices and phonon bands to control umklapp phonon-phonon scattering are described. The potential to exploit inherent amorphous silicon structure as well as the engineering (post film deposition) of di-hydride distributions to induce phonon forbidden bands for significantly reduced multi-phonon scattering is explored. The indirect optical band gap of small domain (and possibly amorphous) silicon [3] provides the physical basis for the transduction of phonon and optical energies. Experimental methods for the post-deposition introduction of phonon scattering structure, the transduction of phononic information to optical information, and experimental approaches including the use of micro-Raman to probe phonon spectra and transport are described. The prospects of a fully integrated phononic, photonic, electronic amorphous silicon technology have been described.

Unveiling the effects of post-deposition treatment with different alkaline elements on the electronic properties of CIGS thin film solar cells

2014 ◽  
Vol 16 (19) ◽  
pp. 8843 ◽  
Author(s):  
Fabian Pianezzi ◽  
Patrick Reinhard ◽  
Adrian Chirilă ◽  
Benjamin Bissig ◽  
Shiro Nishiwaki ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Electronic Properties ◽  
Thin Film Solar Cells ◽  
Cigs Thin Film ◽  
Post Deposition

Quick and Practical Cleaning Process for Silicon Carbide Epitaxial Reactor

2018 ◽  
Vol 924 ◽  
pp. 96-99
Author(s):  
Kohei Shioda ◽  
Keisuke Kurashima ◽  
Hitoshi Habuka ◽  
Hideki Ito ◽  
Shinichi Mitani ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Carbon Film ◽  
Film Surface ◽  
Chemical Vapor ◽  
Pyrolytic Carbon ◽  
Film Deposition ◽  
Carbon Surface ◽  
Cleaning Process ◽  
Silicon Carbide Film ◽  
Carbon Coated

In order to develop a quick and practical cleaning process for the silicon carbide chemical vapor deposition reactor, the pyrolytic carbon-coated susceptor was used. The 30-μm-thick silicon carbide film was formed on the susceptor; the film was cleaning by chlorine trifluoride gas at 460 °C for 15 min. The remained fluorine was removed by the annealing at 900 °C in ambient hydrogen. The pyrolytic carbon surface did not suffer from any damage, because the pyrolytic carbon film surface morphology after the cleaning process was the same as that before the silicon carbide film deposition.

Variation of thin film deposition rate on SS 314 with the variation of gas flow rate using CVD

2011 ◽  
Vol 63 (6) ◽  
pp. 433-439 ◽  
Author(s):  
Mohammad Asaduzzaman Chowdhury ◽  
Dewan Muhammad Nuruzzaman ◽  
Khaled Khalil ◽  
Mohammad Lutfar Rahaman
Keyword(s):  
Thin Film ◽  
Deposition Rate ◽  
Flow Rate ◽  
Gas Flow ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Gas Flow Rate ◽  
Film Deposition Rate

scholarly journals Effects of post-deposition CdCl2 annealing on electronic properties of CdTe solar cells

Solar Energy ◽  
2020 ◽  
Vol 211 ◽  
pp. 938-948
Author(s):  
Sanjoy Paul ◽  
Sandeep Sohal ◽  
Craig Swartz ◽  
Deng-Bing Li ◽  
Sandip S. Bista ◽  
...  
Keyword(s):  
Solar Cells ◽  
Electronic Properties ◽  
Cdte Solar Cells ◽  
Post Deposition

Rapid Diffusion of Molybdenum Trace Contamination in Silicon

1984 ◽  
Vol 36 ◽  
Author(s):  
S. P. Tobin ◽  
A. C. Greenwald ◽  
R. G. Wolfson ◽  
D. L. Meier ◽  
P. J. Drevinsky
Keyword(s):  
Diffusion Coefficient ◽  
Transition Metals ◽  
Lower Limit ◽  
Minority Carrier ◽  
Diffusion Length ◽  
Deep Level ◽  
Depth Profiling ◽  
Epitaxial Layers ◽  
Epitaxial Silicon ◽  
Rapid Diffusion

ABSTRACTMolybdenum contamination has been detected in silicon epitaxial layers and substrate wafers after processing in any one of several epitaxial silicon reactors. Greatly reduced minority carrier diffusion lengths and lifetimes are consistent with Mo concentrations measured by DLTS in the 1012 and 1013 cm−3 ranges. Depth profiling of diffusion length and the Mo deep level show much greater penetration than expected from previous reports of Mo as a slow diffuser. The data indicate a lower limit of 10−8 cm2/sec for the diffusion coefficient of Mo in silicon at 1200°C, consistent with high diffusivities measured for other transition metals.

From meandering to straight grain boundaries: Improving the structures of artificially induced grain boundaries in superconducting YBa2Cu3Oy bicrystals

1997 ◽  
Vol 12 (11) ◽  
pp. 3029-3035 ◽  
Author(s):  
Xiao-Feng Zhang ◽  
Volk R. Todt ◽  
Dean J. Miller
Keyword(s):  
Thin Film ◽  
Grain Boundaries ◽  
Film Deposition ◽  
Ybco Bulk ◽  
Transmission Electron ◽  
Ybco Superconductors ◽  
Film Deposition Rate ◽  
Melt Texture ◽  
Key Aspects ◽  
Misorientation Angles

This paper presents several key aspects of our approach to preparing artificially induced [001] tilt grain boundaries (GB's) with uniform, well-defined structures in YBa2Cu3Oy (YBCO) superconductors. GB structures formed in thin film and bulk bicrystals, respectively, will be compared. In YBCO thin film bicrystals, meandering rather than planar GB's are formed. Using a low film deposition rate has been demonstrated to reduce the magnitude of meander significantly, but complete elimination of the meander has not yet been accomplished. Thus, we have developed a dual-seeded-melt-texture process to produce uniform, planar GB's with controllable misorientation angles in YBCO bulk bicrystals. Transmission electron microscopy (TEM) studies reveal a remarkably planar and simple configuration on different length scales. Such a simple structure allows for an insightful interpretation of transport behavior across individual GB's.

Thin Film Deposition and Transport in 2223 Bi‐Sr‐Ca‐Cu‐O

1989 ◽  
Vol 169 ◽  
Author(s):  
J.T. Kucera ◽  
D.G. Steel ◽  
D.W. Face ◽  
J.M. Graybeal ◽  
T.P. Orlando ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
X Ray Diffraction ◽  
Post Deposition Annealing ◽  
X Ray ◽  
Annealing Conditions ◽  
Sensitive Function ◽  
Post Deposition

AbstractWe have reproducibly prepared thin films of Bi‐Sr‐Ca‐Cu‐O with Tc ≥ 105K. Depositions were done at ambient temperature with a subsequent post‐deposition anneal, and did not include lead substitution. X‐ray diffraction data indicates a majority fraction of the 2223 phase. These films possess very large grains of the order of 20‐30 u.m in size. Post‐deposition annealing conditions are a sensitive function of composition. Detailed transport measurements as a function of temperature and magnetic field have been obtained.

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