Relaxation oscillations in a capacitive discharge chamber connected to a peripheral grounded chamber

Abstract

We have observed relaxation oscillations in an argon capacitive discharge connected to a peripheral grounded chamber through a slot with dielectric spacers. The oscillations, observed from time-varying optical emission of the main discharge chamber, show, for example, a high frequency (∼40kHz) relaxation oscillation at 100mTorr, with absorbed power near that for peripheral breakdown, and a low frequency (∼3Hz) oscillation, at higher absorbed power. The high frequency oscillation is found to ignite a plasma in the slot, but usually not in the periphery. We interpret the high frequency oscillations using an electromagnetic model of the slot impedance, coupled to a circuit analysis of the system including the matching network. The model results are in general agreement with the experimental observations and indicate a variety of behaviors dependent on the matching conditions.

Diagnostic Study of an RF-Capacitively Coupled Plasma: The Breakdown of the Peripheral Gap Region

“…It forms one or more striations, and the striations can be either stagnant or continuously circling around the grounding stage with a non-constant frequency. Such a phenomenon has been reported 16) and was termed plasmoid in some literature. 12) Although the rf voltage above which this breakdown occurs is reproducible, the non-uniform plasma appearance in the peripheral region and the position where the striations are located do not behave in a controllable manner.…”

“…The unintentional breakdown in this region has been reported by several researchers. [14][15][16] Lieberman et al reported the peripheral region breakdown observed in a parallel-plate, capacitively coupled plasma chamber consisting of a peripheral region connected to the main chamber through an annular dielectric slot. Experimental work and numerical simulation revealed that this peripheral region breakdown is greatly influenced by the potential of the bulk plasma adjacent to the peripheral region as well as the diffusion of the charged species from the bulk plasma to the peripheral region.…”

“…14) The behavior of such a breakdown is a complex function of several chamber characteristics and process parameters such as the gap of the dielectric slot, the gas pressure, and the plasma chemistry. For example, Kim et al 15,16) numerically simulated this peripheral breakdown and concluded that this unintentional breakdown can be eliminated by a proper chamber design. The occurrence and the strategy of the elimination of such an unintentional breakdown therefore becomes an important topic of study.…”

High and low frequency relaxation oscillations in a capacitive discharge plasma

“…We determined the mode characteristics with Maxwell equations, of which the detailed discussion may be found in our previous paper. [5]…”

Low-Frequency Relaxation Oscillations in Capacitive Discharge Processes

“…We determined the mode characteristics with Maxwell equations detailed discuss in our previous paper. [5] Fig. 4.…”