A Method for Non-Intrusively Determining ion Impact Current Density and Energy Distribution in Capacitively Coupled RF Plasmas

1987 ◽  
Vol 98 ◽  
Author(s):  
S. E. Savas
Keyword(s):  
Energy Distribution ◽  
Current Density ◽  
Computer Code ◽  
Ion Energy ◽  
Capacitively Coupled ◽  
Rf Plasmas ◽  
Ion Energy Distribution ◽  
Approximate Power ◽  
Ion Impact ◽  
Ion Energy Distributions

ABSTRACTThe dependence of ion current density on the sheath voltage and thickness, and ion energy distributions as functions of the pressure and sheath voltage amplitude have been calculated using a self-consistent computer code, ISHEATH. The current density is found to obey an approximate power law dependence on the amplitude of the sheath voltage, Vs, and the sheath thickness, d, and, when charge exchange collisions are considered, on the collision parameter α ΞNgas · σcx ·d. The ion energy distribution (IED) is found to mainly depend on α: for α ≃l there is only a slight (≃10%) change from the collisionless case; for a ≤ 10 the IED is peaked at an energy which is much less than the time-average sheath potential.

A Derivation of Ion Energy Distribution Function for Dual Frequencies Capacitively Coupled Plasma

2014 ◽  
Vol 513-517 ◽  
pp. 4253-4256
Author(s):  
Zhu Wen Zhou ◽  
De Liang Chen ◽  
Bo Kong ◽  
Yuan Sheng Wang
Keyword(s):  
Energy Distribution ◽  
Integrated Circuit ◽  
Theory Model ◽  
Low Frequencies ◽  
Ion Energy ◽  
Capacitively Coupled ◽  
Ion Energy Distribution ◽  
Particle In Cell ◽  
Capacitively Coupled Plasma ◽  
Ion Energy Distributions

A model of ion energy distribution of dual frequencies capacitively coupled plasma (CCP) has been investigated, it is important to analyze these phenomenon and mechanism in order to control the microelectronic processes of integrated circuit and develop the base theories of plasma physics. We focused on the function of the ion energy distributions under high and low frequencies (dual frequencies) drive in capacitive discharges, we derived a theory model of the dual frequencies driven IEDs from analyzing theories. The model can analyze and predict the IEDs under different high and low frequencies driven, which results in accurate multi-peaks IEDs and energy width for the given control parameters, particle-in-cell (PIC) simulations are used to verify this model.

scholarly journals Far-Field Plume Characterization of a 100-W Class Hall Thruster

Aerospace ◽  
2020 ◽  
Vol 7 (5) ◽  
pp. 58
Author(s):  
Thibault Hallouin ◽  
Stéphane Mazouffre
Keyword(s):  
Energy Distribution ◽  
Current Density ◽  
Low Voltage ◽  
Ion Current ◽  
Hall Thruster ◽  
Far Field ◽  
Ion Energy ◽  
Ion Energy Distribution ◽  
The Core ◽  
Ion Current Density

The 100 W-class ISCT100-v2 Hall Thruster (HT) has been characterized in terms of far-field plume properties. By means of a Faraday Cup and a Retarding Potential Analyzer, both the ion current density and the ion energy distribution function have been measured over a 180 ∘ circular arc for different operating points. Measurements are compared to far-field plume characterizations performed with higher power Hall thrusters. The ion current density profiles remain unchanged whatever the HT input power, although an asymptotic limit is observed in the core of the plume at high discharge voltages and anode mass flow rates. In like manner, the ion energy distribution functions reveal that most of the beam energy is concentrated in the core of the plume [ − 40 ∘ ; 40 ∘ ] . Moreover, the fraction of low energy ion populations increases at large angles, owing to charge exchange and elastic collisions. Distinct plume regions are identified; they remain similar to the one described for high-power HTs. An efficiency analysis is also performed in terms of current utilization, mass utilization, and voltage utilization. The anode efficiency appears to be essentially affected by a low voltage utilization, the latter originating from the large surface-to-volume ratio inherent to low-power HTs. Experimental results also show that the background pressure clearly affects the plume structure and content.

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