Development of a model for high precursor conversion efficiency pulsed-pressure chemical vapor deposition (PP-CVD) processing
A model of the movement of precursor particles in the unsteady Pulsed-Pressure Chemical Vapour Deposition (PP-CVD) process is developed to study the high conversion efficiencies observed experimentally in this process. Verification of the modelling procedures was conducted through a study of velocity persistence in an equilibrium gas and through Direct Simulation Monte Carlo (DSMC) simulations of unsteady self-diffusion processes. The model results demonstrate that in the PP-CVD process the arrival time for precursor particles at the deposition surface is much less than the reactor pump-down time, resulting in high precursor conversion efficiencies. Higher conversion efficiency was found to correlate with smaller size solvent molecules and moderate reactor peak pressure.