Charged particle transport modelling in silane–hydrogen radio-frequency capacitively coupled discharges

Abstract

This paper reviews the formulation and updates some numerical procedures usually adopted in two-dimensional, time-dependent, fluid models to study the transport of charged particles in radio-frequency capacitively coupled discharges. The model solves the continuity and momentum transfer equations for electrons, SiH 3 +, SiH 2 +, H 3 + and H 2 + positive ions and SiH 3 − negative ions, coupled with Poisson's equation and the electron mean energy transport equation. The electron mean energy transport equations are written as directly obtained from the electron Boltzmann equation. The inertia term in the ion momentum transfer equation is accounted for, by generalising the concept of effective electric field. The model is applied to a cylindrical parallel plate reactor, operating at 13.56 MHz, 100–500 V applied potentials and 68–300 mTorr pressures, for various silane–hydrogen composition mixtures. The effects of silane dilution are especially investigated.