The EEDF in a diamond depositing microwave discharge and the validity of assuming a Maxwellian EEDF

The validity of assuming a Maxwellian electron energy distribution function (EEDF) is examined for the case of a diamond depositing microwave discharge in H 2 (With the effects of the carbon bearing species CH 4 neglected). A Boltzmann kinetic model is developed for computation of the EEDF and this is used to predict rates for electron impact processes of interest. Particular attention is paid to the effects of superelastic and electron-electron collisions. The rate coefficients are compared with those obtained by assuming a Maxwellian EEDF of the same average energy as the calculated EEDF. Under typical reactor conditions, assumption of a Maxwellian EEDF is found to be satisfactory for predicting the H 2 dissociation rate and local energy balance may be used to predict the average electron energy.