A global (volume averaged) model of the nitrogen discharge: I. Steady State: I. Steady state

A global (volume averaged) model is developed for a nitrogen discharge in the steady state for the pressure range 1-100 mTorr. The electron energy distribution function is allowed to vary from a Maxwellian to a Druyvesteyn distribution. Varying the electron energy distribution function from a Maxwellian-like to a Druyvesteyn-like influences mainly the density of excited species, ground state species being more important when the distribution is Druyvesteyn-like. We find that the nitrogen discharge is essentially atomic when the pressure is around 1 mTorr and is highly molecular when the pressure is 100 mTorr. The relative reaction rates for the creation and destruction of nitrogen atoms and atomic ions are explored over the pressure range of interest. The model calculations are compared with measurements found in the literature. There is excellent agreement between the model and the measurements for the electron and ion densities as well as the electron temperature. However, a large discrepancy between the model predictions and the measurements of the nitrogen atom density remains unexplained.