Langmuir probe without RF compensation

Abstract

Langmuir probes with RF compensation are used for measurements of electron concentration, electron temperature and the DC value of plasma potential in RF discharges. In order to obtain all the RF components of plasma potential, simple probes without RF compensation are used. However, it has been believed that these uncompensated probes can not be used for determination of the DC value of plasma potential and of electron concentration and temperature, since their VA characteristics is distorted by the RF current. Consequently, the evaluation of data measured with uncompensated probes was not possible without additional measurement with a RF compensated Langmuir probe. This contribution analyzes the possibility to use uncompensated probes not only for measurement of RF components of plasma potential, but also for measurement of the DC component of plasma potential, electron concentration and electron temperature.

In-situ electron density measurement in inductively coupled plasma using microwave reflectometer by Wi-Fi antenna on wafer

“…However, in the plasma process, the use of radio frequency (RF) may interfere with the measurement signal. Distortion of the plasma characteristics is highly possible owing to perturbation of the plasma by the probe [11,12].…”