Selective generation of excited species in ns pulse/RF hybrid plasmas for plasma chemistry applications

2020 ◽  
Vol 29 (10) ◽  
pp. 104002
Author(s):  
I Gulko ◽  
E R Jans ◽  
C Richards ◽  
S Raskar ◽  
X Yang ◽  
...  
2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Bernardo Vieira Magaldi ◽  
Rodrigo Sávio Pessoa ◽  
Argemiro Soares da Silva Sobrinho

The search for new propulsion devices for corrections and adjustments in the orbits of space systems composed of constellations of satellites in specific arrangements has progressively increased with the growth of requests for data transmission with greater speed and capacity. Electric propulsion is the best solution to reduce the propellant mass, in addition to allowing long mission times. Among the various types of thrusters, electrostatic thrusters have a better-defined physics, making possible the development of computational models for the study and optimization of their operational parameters. A global model was develed for a cylindrical ion thruster with the inductively coupled plasma (ICP) generator originated by the circulation of a radio-frequency current in an inductive coil that surrounds the thruster, having at the output a polarized grid extraction system accelerating the ionized argon gas (propellant). The global model is formed by charged and neutral particle balance equations and energy equations of electrons and gas. Neutral and excited species are accelerated by drift out of the thruster and ionized species accelerated for the reason of the electric field generated by the pair of polarized grids in direct current. The most in-depth study of argon plasma chemistry found that, among the various parameters that interfere with species density, the number of excited species has a direct influence on ionization, although it does not interfere much with ion density, what can be translated into a higher rate ion replacement, which is extremely important to gain thrust and specific impulse.


2002 ◽  
Vol 715 ◽  
Author(s):  
S Warthesen ◽  
U Bhandarkar ◽  
S Girshick ◽  
U Kortshagen

AbstractWe have been developing a model to study the nucleation and growth of particles in silane plasmas. Presently we are experimenting with parameters that could potentially be important. It has been found that an increase in the heavy species gas temperature leads to a delay in the nucleation of particles in low pressure silane plasmas. This effect could be useful in tailoring processes for the manufacture of new materials such as polymorphous silicon. We have made an effort to study this effect using a plasma chemistry model. The model includes gas temperature dependent electron attachment and vibrational relaxation of excited species with a view to study their importance in relation to the gas temperature. Preliminary simulation results predict that these two processes do not contribute substantially to slowing the nucleation process when the gas temperature is increased. Extra efforts must be made to study this potentially important effect.


2003 ◽  
Vol 762 ◽  
Author(s):  
C. Smit ◽  
D.L. Williamson ◽  
M.C.M. van de Sanden ◽  
R.A.C.M.M. van Swaaij

AbstractExpanding thermal plasma CVD (ETP CVD) has been used to deposit thin microcrystalline silicon films. In this study we varied the position at which the silane is injected in the expanding hydrogen plasma: relatively far from the substrate and close to the plasma source, giving a long interaction time of the plasma with the silane, and close to the substrate, resulting in a short interaction time. The material structure is studied extensively. The crystalline fractions as obtained from Raman spectroscopy as well as from X-ray diffraction (XRD) vary from 0 to 67%. The average particle sizes vary from 6 to 17 nm as estimated from the (111) XRD peak using the Scherrer formula. Small angle X-ray scattering (SAXS) and flotation density measurements indicate void volume fractions of about 4 to 6%. When the samples are tilted the SAXS signal is lower than for the untilted case, indicating elongated objects parallel to the growth direction in the films. We show that the material properties are influenced by the position of silane injection in the reactor, indicating a change in the plasma chemistry.


2004 ◽  
Vol 1029 (1) ◽  
pp. 405-407 ◽  
Author(s):  
MARCUS SVENSSON ◽  
BENGT JOHANSSON-LINDBOM ◽  
MARC-ANDRÉ WURBEL ◽  
BERNARD MALISSEN ◽  
GABRIEL MÁRQUEZ ◽  
...  

Author(s):  
Marcus A. Worsley ◽  
Stacey F. Bent ◽  
Stephen M. Gates ◽  
Nicholas C. M. Fuller ◽  
Willi Volksen ◽  
...  

2000 ◽  
Vol 266-269 ◽  
pp. 675-679 ◽  
Author(s):  
Vikram L Dalal ◽  
Sohail Haroon ◽  
Zhiyang Zhou ◽  
Tim Maxson ◽  
Kay Han
Keyword(s):  

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