Thumbnail
Access Restriction
Open

Author Bora, B.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PLASMA PHYSICS AND FUSION TECHNOLOGY ♦ ASYMMETRY ♦ ELECTRIC POTENTIAL ♦ ELECTRODES ♦ FLOW MODELS ♦ HARMONICS ♦ IONS ♦ MHZ RANGE ♦ NONLINEAR PROBLEMS ♦ PLASMA HEATING ♦ PLASMA SHEATH ♦ RADIOWAVE RADIATION ♦ SYMMETRY ♦ WAVE FORMS
Abstract On the basis of nonlinear global model, a dual frequency capacitively coupled radio frequency plasma driven by 13.56 MHz and 27.12 MHz has been studied to investigate the influences of driving voltages on the generation of dc self-bias and plasma heating. Fluid equations for the ions inside the plasma sheath have been considered to determine the voltage-charge relations of the plasma sheath. Geometrically symmetric as well as asymmetric cases with finite geometrical asymmetry of 1.2 (ratio of electrodes area) have been considered to make the study more reasonable to experiment. The electrical asymmetry effect (EAE) and finite geometrical asymmetry is found to work differently in controlling the dc self-bias. The amount of EAE has been primarily controlled by the phase angle between the two consecutive harmonics waveforms. The incorporation of the finite geometrical asymmetry in the calculations shift the dc self-bias towards negative polarity direction while increasing the amount of EAE is found to increase the dc self-bias in either direction. For phase angle between the two waveforms ϕ = 0 and ϕ = π/2, the amount of EAE increases significantly with increasing the low frequency voltage, whereas no such increase in the amount of EAE is found with increasing high frequency voltage. In contrast to the geometrically symmetric case, where the variation of the dc self-bias with driving voltages for phase angle ϕ = 0 and π/2 are just opposite in polarity, the variation for the geometrically asymmetric case is different for ϕ = 0 and π/2. In asymmetric case, for ϕ = 0, the dc self-bias increases towards the negative direction with increasing both the low and high frequency voltages, but for the ϕ = π/2, the dc-self bias is increased towards positive direction with increasing low frequency voltage while dc self-bias increases towards negative direction with increasing high frequency voltage.
ISSN 1070664X
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-10-15
Publisher Place United States
Journal Physics of Plasmas
Volume Number 22
Issue Number 10


Open content in new tab

   Open content in new tab