Discharge structure theory of highly electronegative plasma and its hierarchy and interdisciplinary meanings

In this work, a systematic theory of a discharge structure for highly electronegative plasma is developed using a self-consistent fluid model simulation based on the finite element method. The highly electronegative plasma is selected to be the inductively coupled Ar/SF6 plasma source, with the reactive SF6 concentration being 10% and in a pressure range of 10–90 mTorr. The discharge structure is classified as the transport-dominated regime, the transport and chemistry self-balanced regime, and the chemistry-dominated regime. At a low pressure of 10 mTorr, the parabola feature of core plasma, the stratification of the whole discharge area into electronegative core and electropositive halo, the anion potential barrel, and the dipole and capacitor models of the double layer characterize the discharge structure of the transport-dominated regime. With increasing pressure, the recombination loss of ions becomes significant and the discharge structure is characterized by an ellipse profile. Meanwhile, the regions of the double layer and electropositive halo are strikingly shrunk, which means that the plasma of the transport and chemistry self-balanced regime is a closed system and probably does not need the shield of the chamber anymore. The dimensional analysis shows that the recombination can be transformed into drift flux, which balances the ambi-polar diffusion of plasma species. Within the range of pressures considered, the simulation shows that astro-structures are embedded in the parabolic and elliptic profiles. By observing the characteristics of astro-structures, the self-coagulation theory and quasi-Helmholtz equation are built based on the free diffusion and negative chemical source. This is the chemistry-dominated regime and is defined as a tight type of self-balance since the inertia is lost automatically in the unsteady state continuity equations of anions after counteracting the diffusion and recombination. At a high pressure of 90 mTorr, the mixture of a dispersed but closed ellipse background and an astro-structure inlayed therein implies the wave–particle duality of quantum mechanics. In addition, the interdisciplinary meanings of the discharge structure hierarchy of electronegative plasma with astrophysics, geophysics, and nuclear and atomic physics are presented. The electrons that have a negative chemical source in the periphery of astro-structures are self-coagulated at the collapse of the ambi-polar diffusion potential that provides a free diffusion component, and the chemical potential is formed. The electron Boltzmann’s balance does not exist anymore due to its weak self-coagulation behavior of the periphery.