Numerical and experimental investigation of the effect of side injectors on the deposition rate near the wafer edge during atmospheric pressure chemical vapor deposition

Abstract

In this study, the effect of side injection on the deposition rate near the wafer edge is investigated through a numerical simulation and in experimental studies. The main purpose is to maintain the uniformity of the silicon epitaxial layer in region of the wafer edge. The results indicate that the deposition rate near the wafer edge can be changed when the momentum of the jet is sufficient to push the streamlines originating from the side injector to touch the wafer edge. The jet momentum can be increased by increasing the inlet velocity and the Trichlorosilane (TCS) mass fraction of the side injector. The deposition rate in the wafer edge region increases when the TCS mass fraction is higher. It is clear that the momentum of the side injector jet determines the region affected, while the TCS mass fraction changes the deposition rate in the affected region. Both experimental and numerical results show that with a suitable jet velocity and TCS mass fraction, the deposition rate in the edge region can be tuned while maintaining almost the same deposition rate in the central region of the wafer. The non-uniformity caused by a sudden drop in the deposition rate in the edge region of the wafer without the use of side injector can be significantly improved by installing a side injector and applying the proper operating conditions. The numerical results are in good agreement with the experimental ones.