AVS 49th International Symposium
    Plasma Science Tuesday Sessions
       Session PS+MS-TuM

Paper PS+MS-TuM2
High-energy EEDF Tail Detection in High-frequency Discharges

Tuesday, November 5, 2002, 8:40 am, Room C-105

Session: Plasma Diagnostics and Sensors
Presenter: J. Kudela, ANELVA Corporation, Japan
Authors: J. Kudela, ANELVA Corporation, Japan
K Suzuki, ANELVA Corporation, Japan
Y. Nakagawa, ANELVA Corporation, Japan
Y. Numasawa, ANELVA Corporation, Japan
T. Beppu, RITE, Japan
Correspondent: Click to Email
It is well-known that the enhanced high-frequency (HF) fields in the oscillating plasma sheaths can lead to generation of high-energy electrons. At sufficiently low gas pressures, this phenomenon is crucial for the discharge maintenance. However, the phenomenon may also cause the discharge instabilities. The detection of the high-energy tail in the electron energy distribution function (EEDF) in HF discharges is, therefore, of a particular interest from the scientific point of view. It is also important from the technological point of view. The high-energy electrons are determining factor in processing plasmas affecting the discharge chemistry in the plasma volume, and on the processing surface as well. Moreover, on the processing surface, the high-energy electrons may also be responsible for undesired physical processes like charge damage. In our work, we illustrate the detection of high-energy electrons by electrostatic probes in HF discharges at two different frequencies, 2.45GHz and 60MHz. In the microwave band (2.45GHz), the detection of the high-energy electrons is rather simple and it requires only direction-sensitive probes.@footnote 1@ Similar technique is applied to the VHF band (60 MHz) discharges. In these discharges, however, a proper probe compensation is necessary. The conventional compensation methods, which are based on sensing floating potential fluctuations around the probe tip, lose information about the EEDF tail. We propose a method that can lead to detection of high-energy electrons, as well as to the diagnostics of the VHF discharges. This work is supported by NEDO. @FootnoteText@ @footnote 1@ J. Kudela, T. Terebessy, and M. Kando: Hot electrons and EEDF-anisotropy in large-area surface-wave discharges; Proc. IV Int. Workshop Microwave Discharges: Fundamentals and Applications, Sept. 18-22, 2000, Zvenigorod, Russia; ed. Yu.A. Lebedev (Yanus-K, Moscow, 2001), p.63.