A plasma chemistry model for H₂/SiH₄ mixtures used in PECVD processes

Abstract

Plasma chemical processes in H2/SiH4 discharges are critically reviewed. A model set of reactions is proposed which includes temperature and pressure-dependent reaction rates and describes SiyHx (y ≤ 3) chemistry. Using a 2D fluid plasma simulator, the model has been tested under three different set of operating conditions. First, it has been validated against the experimental benchmark data [1]. Based on considerations of atomic hydrogen content, the branching of SiH4 dissociation channels and the H surface loss probability have been defined more accurately. Then, simulations have been also performed for the plasma source of a PECVD tool from Meyer Burger Germany. A very good agreement between the computed and experimentally determined deposition rates can be stated.