Limitations of the independent control of ion flux and energy distribution function in high-density inductively coupled chlorine plasmas

Abstract

Using a self-consistent plasma model coupled with Maxwell's equations, the limitations of independent control of ion fluxes and their energy distribution functions extracted from the high-density inductively coupled chlorine plasma are studied. Two extreme cases of discharge power are considered: 100 W and 1 kW. We find that in the low-power case, plasma is mainly generated by electromagnetic waves while the radio-frequency biased electrode primarily enables plasma ion extraction. Therefore, the ion fluxes and distribution functions are controlled independently. For the high-power case of 1 kW, the bias electrode significantly contributes to plasma generation but has only a small effect on sheath voltage. As a consequence, independent control of ion fluxes and distribution functions becomes impossible. Namely, the increase in the power driving the radio-frequency electrode leads to the increase in the ion fluxes but has little effect on their energy and angular distributions.

Investigation of the dual-frequency bias effect on inductively coupled Cl2 plasmas by hybrid simulation

“…However, during the past few years, the application of this hybrid discharge is limited due to the strong coupling effect between the inductive power and capacitive bias power. On one hand, the bias source could not only affect the oscillation of the sheath near the substrate, but also influence the bulk plasma properties [6,[9][10][11][12][13][14]. For instance, Sobolewski and Kim [6] and Lee et al [9,10] found that the ion flux decreased with increasing bias power at high ICP power, while the ion flux appeared to be independent on the bias source at low ICP power.…”

“…Jun et al [13] utilized a Langmuir probe, and they observed that the ion flux first increased and then decreased with bias power. Moreover, Levko et al [14] simulated the hybrid discharge, and they showed that the bias power contributed significantly to the plasma generation at ICP power of 1 kW.…”

“…Furthermore, the EAE is mainly investigated in electropositive or weakly electronegative CCPs, such as Ar, H 2 , H 2 /SiH 4 and O 2 discharges [35,[41][42][43][44][45][46][47][48], and the studies in strongly electronegative gases, such as Cl 2 , are rarely reported. Actually, high-density Cl 2 plasmas have been widely used in the etching process as a preferable reactant with semiconductors, metals and composite ferroelectrics films [14,[49][50][51] Therefore, the purpose of this paper is to employ a hybrid model, i.e. a global model coupled bi-directionally with an ion Monte-Carlo collision (MCC) sheath model, to investigate the EAE on the separate control of the ion flux and ion energy in Cl 2 ICPs with DF bias sources.…”