A floating potential method for measuring ion density

Abstract

A simple method for analyzing cylindrical Langmuir probe curves in a cold-ion plasma is described which yields the ion density in weakly collisional plasmas for which purely collisionless theories give erroneous results. The method is based on an extrapolation to the floating potential of the saturation ion current raised to the 4/3 power. This procedure is not supported by theory but apparently works because effects neglected in the theory tend to cancel.

Langmuir probe data analysis for a magnetized inductive radio-frequency discharge

“…Moreover, by using the inflexion point method, 15 the plasma or space potential V s can also be evaluated without difficulty. Moreover, by using the inflexion point method, 15 the plasma or space potential V s can also be evaluated without difficulty.…”

Measurement and modeling of time- and spatial-resolved wafer surface temperature in inductively coupled plasmas

“…This stems from the complications arising from the inaccuracy of the probe theories, such as the orbital motion theory. [16][17][18] The ion flux probe is a disk ͑planar͒ probe with a 0.4 cm 2 surface area and is dc biased at −40 V to measure the total positive ion current. To suppress the edge effects, the planar probe is surrounded by a 2 mm width guard ring and this ring is biased to the same potential as the probe throughout the measurement.…”

H 2 cold plasma on Pd∕H system at low hydrogen pressure

“…For small negative polarization the probe current shows an exponential trend, while for large negative polarization no saturation is observed due to the cylindrical shape of the probe. 11 An approximate method 12 was used to estimate the electronic temperature T e :…”