The charged-particle power absorption dynamics in capacitively coupled plasmas operated in different CF4-Ar gas mixtures and driven by tailored voltage waveforms is experimentally investigated by phase-resolved optical emission spectroscopy in conjunction with kinetic simulations and an analytical model. Singleand triple-frequency ‘peaks’and ‘valleys’-type waveforms (generated as a superposition of multiple consecutive harmonics of 13.56 MHz) are studied at pressures of 20 and 60 Pa with 25mm electrode gap and 150 V total driving voltage amplitude to determine the effects of the tailored driving voltage waveform in different gas mixtures on the density profiles of the particle species, the electronegativity, the DC self-bias, and the excitation/ionization dynamics. As the argon content in the buffer gas is increased, the discharge switches from the drift-ambipolar (DA) power absorption mode to the α-mode. This transition occurs due to the disappearance of the bulk and ambipolar electric fields as the electronegativity of the plasma decreases with increasing argon content. This effect is more pronounced at higher pressures, where the negative ion density is higher. We observe a significant change in the plasma’s symmetry, DC self-bias, and mean electron energy as a result of the DAto α-mode transition. At 60 Pa the simulation reveals a drastic increase of the spatially averaged electronegativity induced by increasing the argon admixture from 20% to 30%. This counterintuitive finding is explained by the effect of this admixture on the spatio-temporal electron dynamics. Finally, the generation of the DC self-bias as a function of the argon content is understood by the analytical model based on these fundamental insights into the plasma physics.

中文翻译：

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控制由 Ar 和 CF ₄混合物中的定制电压波形驱动的电容耦合等离子体中的带电粒子动力学

在不同的 CF4-Ar 气体混合物中操作并由定制电压波形驱动的电容耦合等离子体中的带电粒子功率吸收动力学通过相分辨光学发射光谱结合动力学模拟和分析模型进行实验研究。在 20 和 60 Pa 的压力、25mm 的电极间隙和 150 V 的总驱动电压幅度下研究了单频和三频“峰”和“谷”型波形（作为 13.56 MHz 的多个连续谐波的叠加生成），以确定不同气体混合物中定制驱动电压波形对粒子密度分布、电负性、直流自偏压和激发/电离动力学的影响。随着缓冲气体中氩含量的增加，放电从漂移双极 (DA) 功率吸收模式切换到 α 模式。这种转变的发生是由于体电场和双极电场的消失，因为等离子体的电负性随着氩含量的增加而降低。这种效果在负离子密度较高的高压下更为明显。我们观察到由于 DAto α 模式跃迁，等离子体的对称性、直流自偏置和平均电子能量发生了显着变化。在 60 Pa 时，模拟显示通过将氩气混合物从 20% 增加到 30% 引起的空间平均电负性急剧增加。这种违反直觉的发现可以通过这种混合物对时空电子动力学的影响来解释。最后，