THERMODYNAMIC-EQUILIBRIUM AND MASS-TRANSPORT COUPLED MODELING OF THE CHEMICAL-VAPOR-DEPOSITION PROCESS

We present a coupled modelling approach involving mass transport and l ocal thermochemical equilibrium in the gas phase and at the deposition surface of the chemical vapour deposition (CVD) process. The theoreti cal problems arising from the combination of the two approaches are sh own and a solution procedure is proposed. Selected results of thermody namic and mass transport analysis and of the coupled approach show tha t, for the deposition of Si1-xGex solid solution at 1300 K, the thermo dynamic heterogeneous stability of the reactive gases and thermal diff usion lead to the depletion of germanium in the deposit.