Numerical simulation on turbulent flows in vertical chemical vapor deposition reactors

The issue of turbulence in chemical vapor deposition (CVD) reactors has received little attention, since the use of laminar flow conditions in the conventional operation of CVD reactors has been developed as a general preference, contrast to the common preference for turbulent flow conditions in other fields of chemical reactor operation. The turbulent flow can cause the instantaneous heat transfer to be highly nonuniform; however, on average the heat flux may be uniform in some certain part. It is not necessarily a problem in CVD for an instantaneously nonuniform deposition, and obtaining a uniform deposition is essential averaged over the required growth time. So it is worth to explore how to employ turbulent flow properties for efficient and uniform deposition in CVD. In this study, the effect of turbulence on the CVD process in a single wafer reactor is numerically studied with large eddy simulations (LES). The flow and temperature fields are obtained for the cases with different flow Reynolds number, Rayleigh number, geometric and other parameters. The time-averaged heat transfer (Nusselt number) is shown. Some optimum methods and designs to get much better uniformity characteristics across a large part of the wafer are discussed for the turbulent vertical CVD reactors.