Measurements of Electron Energy Probability Functions in inductively coupled plasma with laser Thomson scattering

Electron energy probability functions (EEPFs) having a fine resolution of electron energy were measured in low-pressure inductively coupled plasma with laser Thomson scattering method (LTS) at various plasma conditions (rf powers and gas pressures) and compared with the EEPFs measured by a single Langmuir probe (SLP) at the same experimental conditions. The result of LTS showed that the measured electron density normally increases with the rf power and the gas pressure, and the electron temperature decreased with the rf power and the gas pressure. This result have a good agreement not only with the previous reports qualitatively but also with our SLP measurement result quantitatively [15]. The reasons for the discrepancy between two methods in absolute value might be expected to these facts as following: the probe perturbation effect from the probe holder volume, RF noise, and not sufficient signal level of laser Thomson scattering.