Particle composition of high-pressure SF/sub 6/ plasma with electron temperature greater than gas temperature

Numerical computation was performed to derive particle compositions of high-pressure SF/sub 6/ plasmas in which the electron temperature T/sub e/ is greater than the gas temperature T/sub g/. The effective excitation temperature T/sup ex/ for each of particles was proposed to express the distribution of particles in excited states. Furthermore, the relation equations for chemical equilibrium in a two-temperature plasma were developed on the basis of the second law of thermodynamics. At fixed T/sub g/ in the range of 6000-9000 K, the increasing T/sub e/ from 9000-20 000 K encourages the dissociation and ionization of particles, causing the composition of SF/sub 6/ plasma at 0.1 MPa to differ markedly from the composition under the condition of thermal equilibrium.