Comparison of circular TM₀₁ and TM₁₁ modesgenerated electron cyclotron resonance microwave discharges-a MonteCarlo simulation study

摘要

Plasma density, ionization percentage, and electron energydistribution (EED) are the concerning factors of plasma sources forvarious industrial applications. It has been shown experimentally thatthe electron cyclotron resonance (ECR); plasma can be generated in lowbackground pressure conditions and has high plasma density. Thenumerical simulation further indicates that the EED of an ECR plasma hasa high energy tail, and can be characterized by two temperaturecomponents. In this study, the electron behavior in two ECR microwavedischarges maintained, respectively, by the TM₀₁ andTM₁₁ mode fields of a cylindrical waveguide have beeninvestigated via Monte Carlo simulations. Since ECR microwave dischargehas high degree of ionization (>1%), a self-consistent simulation ofthe plasma dynamics is achieved through the use of the ponderomotive andgrad-B forces. Accumulation of negative charges on the boundary surfacesets up a sheath whose influence is also taken into account. The timeaveraged, spatially dependent EED is computed self-consistently byintegrating electron trajectories subjected to the microwave fields, thedivergent background magnetic field, the space charge field, and thesheath field, and taking into account electron-electron collisions andcollisions with the neutral hydrogen atoms