The investigation of etching kinetics and surface conditions for KNbxOy thin films in CF4 + Ar and Cl2 + Ar inductively coupled plasmas was carried out. The variable processing parameters were Ar content in a feed gas (0–75% Ar), gas pressure (4–10 mTorr) and input power (400–700 W) at constant bias power of 100 W. The combination of plasma diagnostics by Langmuir probes and plasma modeling provided the data on internal plasma parameters, gas-phase chemistry and steady-state densities of plasma active species. The compositional changes of the etched surfaces were investigated using X-ray photoelectron spectroscopy (XPS). It was found that the fluorine-based etching chemistry provides the much lower halogen atom flux together with the much higher KNbxOy etching rate under the condition of quite close ion momentum fluxes in both gas systems. The correlations between measured etching rates and model-predicted fluxes of active species suggested the neutral-flux-limited etching regime with the much lower effective reaction probability between KNbxOy and Cl atoms. The last effect may be related to lower volatility of NbClx compared with NbFx (that is confirmed by XPS data) as well as to the higher energy threshold for KNbxOy + Cl reaction.

中文翻译：

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使用基于氟和氯的等离子体化学物质对 KNbxOy 薄膜的蚀刻动力学和表面条件

对 KNbxOy 薄膜在 CF4 + Ar 和 Cl2 + Ar 电感耦合等离子体中的蚀刻动力学和表面条件进行了研究。可变处理参数是进料气中的 Ar 含量（0-75% Ar）、气压（4-10 mTorr）和输入功率（400-700 W），恒定偏置功率为 100 W。 Langmuir 探针和等离子体建模提供了有关等离子体活性物质的内部等离子体参数、气相化学和稳态密度的数据。使用X射线光电子能谱（XPS）研究蚀刻表面的成分变化。发现在两种气体系统中的离子动量通量非常接近的条件下，氟基蚀刻化学提供低得多的卤素原子通量以及高得多的KNbxOy蚀刻速率。测量的蚀刻速率与模型预测的活性物质通量之间的相关性表明，KNbxOy 和 Cl 原子之间有效反应概率低得多的中性通量限制蚀刻机制。最后一个影响可能与 NbClx 与 NbFx 相比较低的挥发性（由 XPS 数据证实）以及 KNbxOy + Cl 反应的较高能量阈值有关。