The modelling routes for the chemical vapour deposition process: application to Si1−xGex deposition

The purpose of this article is to present the modelling routes for the chemical vapour deposition process with a special emphasis on mass transport models with near local thermochemical equilibrium imposed in the gas-phase and at the deposition surface. The theoretical problems arising from the linking of the two selected approaches, thermodynamics and mass transport, are shown and a solution procedure is proposed. As an illustration, selected results of thermodynamic and mass transport analysis and of the coupled approach showed that, for the deposition of Si1−xGex solid solution at 1300 K (system SiGeClHAr), the thermodynamic heterogeneous stability of the reactive gases and the thermal diffusion led to the germanium depletion of the deposit.