Global model for pulsed inductively coupled plasma sources: Effect of edge-to-center density ratio and electron heating

Abstract

The volume-averaged global plasma model has been widely used to analyze the characteristics of plasma, although the spatial variation of plasma parameters cannot be obtained from it. It has also been used to obtain temporal plasma parameters for pulsed plasma sources. In this work, we analyzed the effect of an edge-to-center density ratio (h factor) and an electron heating model on the plasma parameters in pulsed plasma simulations using the global model for Ar discharges. In most previous pulse simulations using the global model, the h factor has been applied to pulse conditions in the same way it has been applied to radio frequency, and the power absorbed by the electrons was assumed to be equal to the applied power. However, in this work, we considered a time-varying h factor and determined the absorbed power using an analytical electron heating model, solving the spatially averaged transport equations in a self-consistent manner. We found that a decreased h factor increases the plasma density and consequently changes the time dependence of the electron temperature. In addition, the overshoot of the electron temperature is limited at the beginning of the pulse power-on in the self-consistent electron heating model. Our results are of great relevance with respect to the analysis of plasma parameters.