Principle and application of a thermal probe to reactive plasmas.

A thermal probe for plasma diagnostics is introduced. The method is based upon measuring the equilibrium temperature of a conducting sphere as a function of its applied bias. The resulting temperature–voltage characteristic is processed using a theoretical model that accounts for charge and thermodynamic balance. The thermal probe is capable of detecting negative ions and shows sensitivity to certain chemical reactions. Measurements performed in Ar, Ar/SF[sub 6], and O[sub 2] show good agreement among the plasma parameters using thermal and Langmuir probes. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]