Laser-Induced Deposition of Silicon Films and Cars Diagnostics

1983 ◽  
Vol 29 ◽  
Author(s):  
M. Hanabusa ◽  
H. Kikuchi
Keyword(s):  
Gas Phase ◽  
Chemical Vapor ◽  
Silicon Films ◽  
Main Body ◽  
Gas Phase Reactions ◽  
Phase Dynamics ◽  
Double Peaks ◽  
Deposition Processes ◽  
Laser Cvd ◽  
Anti Stokes

ABSTRACTVarious laser-based deposition methods for preparation of silicon films have been reviewed briefly with emphasis on laser chemical vapor deposition (CVD). The main body of this paper is concerned with CO2laser CVD of silane. This is interesting because the observed dependence of deposition rates on laser wavelengths indicates that gas-phase reactions are involved in deposition processes and therefore we can apply a powerful new diagnostic means, coherent anti-Stokes Raman spectroscopy (CARS), to examine gas-phase dynamics. From N2CARS thermometry the CO2laser beams were found to raise the temperature of the gas containing silane, when they were tuned to absorption lines of SiH4. Silane CARS spectra were characterized by a complicated profile with double peaks. We interpreted the shape of the spectra as arising from excitation of rotational levels following gas-phase reactions. Applying this interpretation, we can judge how SiH4molecules are disturbed differently according to CO2laser wavelengths and a distance from a substrate.

DEVELOPMENT OF HIGHLY CONDUCTIVE BORON-DOPED MICROCRYSTALLINE SILICON FILMS FOR APPLICATION IN SOLAR CELLS

2006 ◽  
Vol 20 (03) ◽  
pp. 303-314 ◽  
Author(s):  
QING-SONG LEI ◽  
ZHI-MENG WU ◽  
JIAN-PING XI ◽  
XIN-HUA GENG ◽  
YING ZHAO ◽  
...  
Keyword(s):  
Solar Cells ◽  
Substrate Temperature ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Silicon Films ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
Boron Doped ◽  
Deposition Processes ◽  
P Type

We have examined the deposition of highly conductive boron-doped microcrystalline silicon (μc- Si:H ) films for application in solar cells. Depositions were conducted in a very high frequency plasma enhanced chemical vapor deposition (VHF PECVD) chamber. In the deposition processes, various substrate temperatures (TS) were applied. Highly conductive p-type microcrystalline silicon films were obtained at substrate temperature lower than 210°C. The factors that affect the conductivity of the films were investigated. Results suggest that the dark conductivity, which was determined by the Hall mobility and carrier concentration, is influenced by the structure. The properties of the films are strongly dependent on the substrate temperature. With TS increasing, the dark conductivity (σd) increases initially; reach the maximum values at certain TS and then decrease. Also, we applied the boron-doped μc- Si:H as p-layers to the solar cells. An efficiency of about 8.5% for a solar cell with μc- Si:H p-layer was obtained.

A Comprehensive Multiphysics, Multiscale Study of Reactor Chamber and Substrate Orientation Effects on Carbon Nanotube Synthesis During Chemical Vapor Deposition Process

2008 ◽  
Author(s):  
Mahmoud Reza Hosseini ◽  
Nader Jalili ◽  
David A. Bruce
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Nanotube ◽  
Temperature Profile ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Physical Property ◽  
Fabrication Process ◽  
Multiphase Model ◽  
Gas Phase Reactions

A comprehensive multiphysics, multiphase model of carbon nanotube (CNT) fabrication process by chemical vapor deposition (CVD) is utilized to study the effects of several physical phenomena inside the quartz tube. The investigations include fluid flow properties, temperature profile and heat transfer as well as diffusion and concentration of carbon species along the substrate. These properties are examined in a great detail for a horizontally placed substrate. For each physical property, the effects of substrate dislocation as well as the angle between substrate and reactor chamber longitudinal axis are investigated. It is shown that the temperature in the gas phase reactions region is significantly lower compared to the temperature profile around the substrate. Based on the obtained results, two new CVD system designs are proposed to enhance the temperature in the reactor chamber section where gas phase reactions take place. Moreover, it is shown that substrate dislocation and angle change result in physical property change such as species concentration on upper and lower substrate surfaces. This study is also applicable to other CVD-based fabrication process such as deposition of any layer, since the methodology of the fabrication process remains the same.

FTIR In Situ Studies of the Gas Phase Reactions in Chemical Vapor Deposition of SiC

1995 ◽  
Vol 142 (7) ◽  
pp. 2357-2362 ◽  
Author(s):  
S. Jonas ◽  
W. S. Ptak ◽  
W. Sadowski ◽  
E. Walasek ◽  
C. Paluszkiewicz
Keyword(s):  
Chemical Vapor Deposition ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Gas Phase Reactions ◽  
In Situ Studies

Gas Phase Reactions Relevant to Chemical Vapor Deposition: Optical Diagnostics

1989 ◽  
Vol 168 ◽  
Author(s):  
D. Burgess
Keyword(s):  
Chemical Vapor Deposition ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Optical Emission ◽  
Laser Photolysis ◽  
Particle Nucleation ◽  
Gas Phase Reactions ◽  
Decomposition Processes ◽  
Rate Of Reaction

AbstractLaser photolysis, optical emission, and laser-induced fluorescence (LIF) were used to investigate laser driven decomposition processes in the gas phase pertaining to the systems: SiH4 → Si (s) and SiH4 → NH3 → Si3N4 (s). These processes are important to silicon/ silicon-nitride chemical vapor deposition, flame-driven gas phase silicon-particle nucleation, and laser-induced processes for materials fabrication. UV laser photolysis was used to generate SiHx and NHx species from silane and ammonia. A number of photofragments were identified by emission from excited states. The rate of reaction of NH2 with silane was measured using LIF to detect NH2 as a function of time following photolysis of ammonia

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