Plasma-relevant fast electron impact study of nitrogen trifluoride

Nitrogen trifluoride (NF₃) is an important molecule in the field of plasma science as an efficient fluorine source in manufacturing very large scale integrated circuits. The dynamic parameters of NF₃, especially its total dissociation cross sections, are extremely important for improving the accuracy of plasma models. However, very few dissociation cross section data exist in experiment. In the present work, the generalized oscillator strengths of the dissociative excited states of NF₃ have been determined at an incident electron energy of 1500 eV and an energy resolution of 70 meV. The corresponding optical oscillator strengths have been obtained by extrapolating the generalized oscillator strengths to the limit of zero squared momentum transfer. The total dissociation cross sections of the dissociative excited states of NF₃ have been obtained systematically from the threshold to 2500 eV with the aid of the BE-scaling method, which give an independent cross-check to the theoretical results. The cross check suggests that the present BE-scaled dissociation cross sections for the singlet excited states can be served as the benchmark data. Based on the detailed analysis, the present BE-scaled dissociation cross sections for the singlet excitations and the shifted theoretical dissociation cross sections of the triplet excitations are recommended for the practical applications in the plasma models. (paper)