In this work, we investigated the possibidlxlity to control both gas-phase chemistry and silicon etching kinetics in C4F8 + O2 + Ar inductively coupled plasma by changes in O2/Ar, C4F8/O2 and C4F8/Ar mixing ratios at the constant fraction of the rest component (50%), gas pressure (10 mTorr), input power (700 W) and bias power (200 W). The combination of plasma diagnostics and modeling tools allowed one: (a) to compare the effects of gas mixing ratios on both steady-state plasma parameters and densities of active species; (b) to figure out key processes which determine the fluorine atom formation/decay balance in each gas system; and (c) to analyze the differences in Si etching kinetics in terms of process-condition-dependent effective reaction probability. It was shown that the maximum changes in gas-phase chemistry take place in O2-rich plasmas due to CFx + O/O(1D) → CFx−1O + F, CFxO + e → CFx−1O + F + e and CFO + O/O(1D) → CO2 + F stepwise dissociation pathways. It was suggested also that the effective probability for Si + xF → SiFx reaction may be controlled by either fluorocarbon film thickness (in C4F8—rich plasmas) or O atom flux (in Ar and O2—rich plasmas) through the balance of adsorption sites on the etched surface.

中文翻译：

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C4F8 + O2 + Ar 气体混合物中的等离子体参数和硅蚀刻动力学：组分混合比的影响

在这项工作中，我们研究了通过改变 O2/Ar、C4F8/O2 和 C4F8/Ar 混合比在 C4F8 + O2 + Ar 电感耦合等离子体中控制气相化学和硅蚀刻动力学的可能性。其余分量 (50%)、气压 (10 mTorr)、输入功率 (700 W) 和偏置功率 (200 W)。等离子体诊断和建模工具的结合允许： (a) 比较气体混合比对稳态等离子体参数和活性物质密度的影响；(b) 找出决定每个气体系统中氟原子形成/衰变平衡的关键过程；(c) 根据工艺条件相关的有效反应概率来分析 Si 蚀刻动力学的差异。结果表明，由于 CFx + O/O(1D) → CFx−1O + F、CFxO + e → CFx−1O + F + e 和 CFO +，气相化学的最大变化发生在富氧等离子体中O/O(1D) → CO2 + F 逐步解离途径。还提出了 Si + xF → SiFx 反应的有效概率可以通过碳氟化合物膜厚度（在 C4F8 富等离子体中）或 O 原子通量（在 Ar 和 O2 富等离子体中）通过吸附位点的平衡来控制。蚀刻的表面。