Equivalent circuit effects on mode transitions in H2 inductively coupled plasmas

Abstract

It is well known experimentally that the circuit matching network plays an important role in the mode transition behavior of inductively coupled plasmas. To date, however, there have been no reports of numerical models being used to study the role of the matching circuit in the transition process. In this paper, a new two-dimensional self-consistent fluid model that couples the components of an equivalent circuit module is developed to investigate the effects of the equivalent circuit on the mode transition characteristics of an inductively coupled, hydrogen plasma. The equivalent circuit consists of a current source, impedance matching network, reactor impedance, and plasma transferred impedance. The nonlinear coupling of the external circuit with the internal plasma is investigated by adjusting the matching capacitance at a fixed input current. The electron density and temperature as well as the electromagnetic fields all change suddenly, and the E to H mode transition occurs abruptly at a certain matching capacitance as the impedance matching of the external circuit is varied. We also analyze the fields and the plasma characteristics during the transition process, especially for the case of the capacitive E mode. V C 2015 AIP Publishing LLC.

Mode Transition and Hysteresis in Inductively Coupled Plasma Sources

“…However, it is difficult for the self-consistent multidimensional models to capture the discontinuity and hysteresis unless the external circuit module is taken into account. In this chapter, the conventional fluid model that describes the pure inductive mode is extended by including the capacitive mode and advanced by introducing an equivalent circuit module [26,27]. The diagram of equivalent circuit is illustrated in Figure 12.…”

“…Besides the above representative features, it still exhibits research values in the topics of reactive gas mixtures, such as O 2 [30], CF 4 /Ar [31], SO 2 [32], ammonia [33] and so on and double hysteresis loop [29], inverse hysteresis [34], spatial characteristics [35], optical emission [36], electrical diagnostics [37], instability of electronegative plasma source [38] and so on. To the author, the exploration of precursors that triggers hysteresis, for instance, metastables and multistep ionizations [13,21], electron energy distribution function [39], power coupling efficiency [40], sheath [24,41], external circuit [26,27] and nonlinear mechanisms [13] and so on, is the most attractive topic. The investigations greatly advance the improvements of analytical theory, numerical modeling, and experimental diagnostics of low-temperature plasma physics.…”

Discontinuity of mode transition and hysteresis in hydrogen inductively coupled plasma via a fluid model

“…The model used in this paper consists of three parts, i.e., the electromagnetic module, equivalent circuit module, and fluid module. The model was elaborately described in our previous work [23] . Hence, in the present paper, only a brief introduction is given.…”

“…This is reasonable since in the real plasma sources it is already found that the variations in the azimuthal direction are indeed of minor importance and most of the present modelings in this type of reactor are conducted in radial and axial two-dimensional space. For more details related to this issue, reference [23] can be referred to.…”

“…In Ref. [23], the effect of the matching effect on the mode transition behavior in a hydrogen ICP was studied with a new fluid model that is based on our previous mode transition simulation work, [24] but is significantly improved by coupling an equivalent circuit module. [23] In this paper, still using the same model, the effect of the external circuit on the mode transitions and especially the hysteresis, as well as the pressure dependence, is systematically investigated.…”