Investigation on development of advanced frequency shift probe

报道了一种用于反应工艺等离子体电子密度测量的平面型频移探针。采用时域有限差分法（FDTD）对鞘层效应进行了电磁场分析，并通过实验验证了计算结果。FDTD模拟表明，在探针周围形成的鞘层导致低估的电子密度相比，真实的密度作为初始条件的模拟。然而，探针天线缝隙宽度的增加抑制了密度低估，并且有效地提高了密度测量的准确性。此外，通过考虑鞘层效应，具有不同狭缝宽度的两个探针的组合使得不仅能够测量电子密度和电子温度。

This paper reports plane-type frequency shift probe for electron density measurements in reactive processing plasmas. The sheath effects were investigated by electromagnetic field analysis with FDTD simulation, and the calculated characteristics were confirmed experimentally. The FDTD simulation revealed that the sheath formed around the probe leads to underestimation of electron density, in comparison to the real density given as an initial condition in the simulation. However, an increase in a slit width of the probe antenna suppressed the density underestimation, and effective for improvement of accuracy of the density measurement. Furthermore, combination of two probes with different slit width enabled measurements of not only electron density and electron temperature by considering the sheath effects.