The Nucleation and Growth of Polycrystalline Silicon Carbide

1990 ◽  
Vol 202 ◽  
Author(s):  
Brian W. Sheldon ◽  
Theodore M. Besmann

ABSTRACTSilicon carbide was deposited from methyltrichlorosilane onto polished polycrystalline SiC substrates at reduced pressure, and the resultant surface morphology was characterized by analyzing the angular spectrum of scattered light which was generated with a He-Ne laser. Light-scattering analyses incorporating specific nucleation and growth models were developed. With these methods, it was possible to analyze the angular scattering spectra and directly measure the nucleation and growth rates. These results were verified by using image analysis to quantify the number and size distribution of surface features that were observed with scanning electron microscopy. The nucleation and growth rates that were obtained by fitting the models to the image-analysis results were in good agreement with the rates obtained from the light-scattering.

1991 ◽  
Vol 250 ◽  
Author(s):  
Brian W. Sheldon ◽  
Philip A. Reichle ◽  
Theodore M. Besmann

AbstractLight-scattering was used to monitor the chemical vapor deposition of silicon carbide from methyltrichlorosilane. The nucleation and growth of the SiC features caused changes in the surface topography that altered the angular scattering spectrum that was generated with a He-Ne laser. These scattering spectra were then analyzed to obtain information about the nucleation and growth processes that are occurring.


1989 ◽  
Vol 168 ◽  
Author(s):  
B. W. Sheldon ◽  
T. M. Besmann

AbstractSurface morphologies created by the chemical vapor deposition (CVD) of silicon carbide were examined with light scattering. Silicon carbide was deposited from methyltrichlorosilane under various conditions to create different surfaces. A helium neon laser was used, and the scattered light was measured over a range of scattering angles. These measurements are compared with scanning electron microscopy (SEM) observations and profilometer measurements of the same surfaces. In theory the scattered light contains all of the information needed to provide a statistical description of a given surface; however, a complete vector theory for the scattering phenomena is too complex to provide any simple basis for experimental analysis. The application and limits of existing descriptions of scattering from a rough surface are discussed.


2001 ◽  
Vol 66 (6) ◽  
pp. 973-982 ◽  
Author(s):  
Čestmír Koňák ◽  
Jaroslav Holoubek ◽  
Petr Štěpánek

A time-resolved small-angle light scattering apparatus equipped with azimuthal integration by means of a conical lens or software analysis of scattering patterns detected with a CCD camera was developed. Averaging allows a significant reduction of the signal-to-noise ratio of scattered light and makes this technique suitable for investigation of phase separation kinetics. Examples of applications to time evolution of phase separation in concentrated statistical copolymer solutions and dissolution of phase-separated domains in polymer blends are given.


Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 359
Author(s):  
Francesco Ruffino

Bimetallic nanoparticles show novel electronic, optical, catalytic or photocatalytic properties different from those of monometallic nanoparticles and arising from the combination of the properties related to the presence of two individual metals but also from the synergy between the two metals. In this regard, bimetallic nanoparticles find applications in several technological areas ranging from energy production and storage to sensing. Often, these applications are based on optical properties of the bimetallic nanoparticles, for example, in plasmonic solar cells or in surface-enhanced Raman spectroscopy-based sensors. Hence, in these applications, the specific interaction between the bimetallic nanoparticles and the electromagnetic radiation plays the dominant role: properties as localized surface plasmon resonances and light-scattering efficiency are determined by the structure and shape of the bimetallic nanoparticles. In particular, for example, concerning core-shell bimetallic nanoparticles, the optical properties are strongly affected by the core/shell sizes ratio. On the basis of these considerations, in the present work, the Mie theory is used to analyze the light-scattering properties of bimetallic core–shell spherical nanoparticles (Au/Ag, AuPd, AuPt, CuAg, PdPt). By changing the core and shell sizes, calculations of the intensity of scattered light from these nanoparticles are reported in polar diagrams, and a comparison between the resulting scattering efficiencies is carried out so as to set a general framework useful to design light-scattering-based devices for desired applications.


2006 ◽  
Vol 23 (2) ◽  
pp. 145-153 ◽  
Author(s):  
Hans Saveyn ◽  
Tran Le Thu ◽  
Ruxandra Govoreanu ◽  
Paul Van der Meeren ◽  
Peter A. Vanrolleghem

2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
Wen-Teng Chang

The present paper evaluates the static and motional feedthrough capacitance of a silicon carbide-based flexural-mode microelectromechanical system resonator. The static feedthrough capacitance was measured by a network analyzer under atmospheric pressure. The motional feedthrough was obtained by introducing various values into the modeling circuit in order to fit the Bode plots measured under reduced pressure. The static feedthrough capacitance was 0.02 pF, whereas the motional feedthrough capacitance of an identical device was about 0.2 pF, which is one order of magnitude larger than the static feedthrough capacitance.


Author(s):  
Gernot Seebacher ◽  
Axel A. Schmidt ◽  
Jochen Offermann

The paper provides background on how bilge water has changed over the years and how technology has enabled manufacturers to stay ahead of the curve by borrowing technological breakthroughs from other areas to the measurement of oil content in the marine environment. Light scattering provides today a universal and reliable method, able to measure the wide range of oils present in a wildly variable and unpredictable bilge water mixture. Bilge water regulations were put in place to reduce the potential of harm to the environment from oily bilge water discharges. Regulations require that instruments verify effluent quality continually during the discharge process, which precludes the adoption for shipboard use of standard laboratory style testing with the associated time delays to complete the analysis. Measuring oil content with the light scattering measuring instrument is a tried and tested means for compliant bilge water verification. State of the art instruments employ sophisticated light measuring systems and they use complex algorithms to convert the scattered light pattern values into oil content reading, thereby considering interference from other than oil suspended matter, they prevent harm to the environment from bilge water discharges. Paper published with permission.


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