Contribution à la modélisation des plasmas de dépôt basse pression

Abstract

The present work develops and tests a computationally model of a DC glow discharge in low pressure. The proposed theoretical model is applied to collisional argon plasma in a reactor consisting of two plane parallel electrodes where the cathode is heated to a voltage of -250 V. The proposed code is based on solving the continuity equation coupled with Poisson's equation and electrons mean energy’s equation. The particles trajectories simulation requires the knowledge of all collisional processes through their collision cross sections. The probability of collision during a free flight time can not be known without performing integrations of non-analytical cross sections. The proposed solution to this problem consists in the application of the "null collision" concept. The simulation is carried out using finite difference method. Matlab software is used to solve the partial differential equations that govern the behavior of the discharge. The study of the pressure, the free flight time, the secondary emission of electrons from the electrode surface and the inter-electrodes distance effect, on the plasma characteristics, confirms the validity of this model.