Ballistic Transport and Reaction Model

EVOLVE is based on the free molecular or "ballistic" transport and reaction model (BTRM) developed by Timothy S. Cale.

Frequency of particle-particle collisions negligible relative to frequency of particle-wall collisions. The film evolves slowly relative to the redistribution of local fluxes. The local film growth rate is governed by heterogeneous reaction mechanisms, and depends on the local species fluxes. Species arrive at the surface from the source volume with well defined, species specific, flux distributions. System specific modifications/extensions are required; e.g., that re-emission is cosine for CVD systems.

Species balance:

BTRM - Solutions

• discretize integrals over angles;
• discretize PDE using 2nd order finite difference;
• discretized equations are solved using nonlinear over-relaxation (NLORM) technique.

Literature references regarding BRTM