Min-Keun Bae

Analysis of Electron Temperature in DC Ar/SF6 Plasma Using Cylindrical and Planar Probes

Electronegative plasmas are generated by adding SF6 gas to a background argon (Ar) DC plasma with parameters of n0 = 1×1010 cm3 and Te = 2 eV. The heating current of the thoriated filament was in the range of 20.5–21.5 A and the plasmas were generated under a discharge condition of 100 V/0.4 A. The amount of negative ions was controlled by adjusting the ratio of flow rate of SF6 = 0–10% to that of Ar. Plasma parameters were measured using cylindrical and planar electric probes. The behavior of electrons, which means the change in a parameter due to negative ion production, is characterized by measuring the floating and plasma potentials, and electron temperature. Electron temperature seems to increase and the potentials decrease with SF6 flow rate.

Measurement of Negatively Charged Dust by Using an Electric Probe in Large RF Helium Plasmas

Abstract We investigated charged dust and its effect on RF plasma by using a planar electric probe in a large-scale device. In background plasmas, the particle density is 108 to 109 cm−3 and the electron temperature is 2 to 4 eV. When dust is contained in plasma, it is negatively charged by electrons attached to the dust. The charged dust density and the charge were calculated by comparing dusty helium plasma to pure helium plasma. Depending on the increase in the amount of dust, the charged dust density increases with the decrease in the charge due to depletion of the electrons in the background plasma. The results show that the charge changes the interactions between the dust and particles in the background plasma.