A model for the discharge kinetics and plasma chemistry during plasma enhanced chemical vapor deposition of amorphous silicon

Abstract

A model for the plasma enhanced chemical vapor deposition of amorphous hydrogenated silicon (a‐Si:H) in rf and dc discharges is presented. The model deals primarily with the plasma chemistry of discharges sustained in gas mixtures containing silane (SiH₄). The plasma chemistry model uses as input the electron impact rate coefficients generated in a separate simulation for the electron kinetics and therefore makes no a priori assumptions as to the manner of power deposition. Radical densities and contributions to film growth are discussed as a function of gas mixture, electrode separation, and locale of power deposition, and comparisons are made to experiment. A compendium of reactions and rate constants for silane neutral and ion chemistry is also presented.