Kinetics driving high-density chlorine plasmas

Abstract

A simple fluid model was developed in order to investigate the driving kinetics of neutral and charged species in high-density chlorine plasmas. It was found that the dissociation degree of Cl2 molecules is directly linked to the power balance of the discharge which controls the electron density. The model was also used to identify those reactions that could be neglected in the particle balance of charged species and those that must be included. Our results further indicate that diffusion losses need to be considered up to a pressure that depends on magnetic-field intensity and reactor aspect ratio. Finally, it is shown that the dominant charged carriers are linked to the dissociation level of Cl2 molecules.

Dry etching of zinc-oxide and indium-zinc-oxide in IBr and BI3 plasma chemistries

“…In general, an increase in ICP source power leads to an increase of both the reactive neutral density (through an increase of the dissociation degree of the reactive molecular species) and the positive ion density [47][48][49]. Moreover, Fig.…”

Experimental and modeling study of O and Cl atoms surface recombination reactions in O2 and Cl2 plasmas

“…For simplicity, the plasma was assumed isothermal, which means that the electron temperature was considered as spatially uniform. This model was found to adequately predict the influence of gas pressure, mag- netic field intensity, and injected power on the electron number density, electron temperature, and number density of the dominant positive ion species [21]. As for the degree of dissociation of Cl 2 , given that electron density and electron temperature are well computed, the only parameter that needs to be adjusted is the recombination coefficient of Cl atoms on chamber walls.…”

“…Details on this plasma reactor, the model, and the recombination coefficients presented here can be found elsewhere [21,34,60]. The plasma is created in a 14.6-cm-diameter fused silica tube and expands from the source region into a large 28-cm-diameter SS processing chamber.…”

“…10a were used as inputs in the isothermal fluid model described in ref. [21]. For a given electron density (and thus for a given axial position), the Cl atom recombination coefficient was varied between 10 -3 and 10 -1 to match the meas- ured percent dissociation of Cl 2 (Fig.…”

“…As a result, the recombination coefficients determined from beam studies for a given atom on a given material often vary by orders of magnitude with respect to those obtained under dynamic plasma conditions. For example, Kota et al [19] found recombination coefficients for Cl atoms at 300 K of 0.2 for anodized Al and 0.7 for stainless steel (SS) in a molecular beam experiment while the values for these materials determined in high-density Cl 2 plasma reactors are usually in the 0.01-0.04 range [20][21][22]. An important factor influencing the surface recombination rates and thus the materials processing rates is the so-called "conditioning" or "seasoning" of the surface following exposure to reactive plasmas [23][24][25][26].…”