Comparison of electron property measurements in an inductively coupled plasma made by Langmuir probe and laser Thomson scattering techniques

Langmuir probes and Thomson scattering are two independent methods of measuring electron properties in glow discharges. In this article, measurements of electron properties of an inductively coupled plasma were made using both methods, and the results obtained with the probe were compared with those obtained using the more reliable laser method. The values of electron temperature and density obtained by both methods were similar over a range of plasma conditions but significant differences in the electron energy distribution function were observed. In addition, clear evidence was obtained that the presence of the probe perturbed the discharge. The advantages and disadvantages of each method are discussed with respect to the suitability of each technique for measuring electron properties in inductively coupled glow discharges. (C) 1999 American Vacuum Society. [S0734-2101(99)03402-8].