This paper investigates a new CVD reactor geometry to deposit uniform films on large area substrates at atmospheric pressure. Calculations have been performed for a wide range of parameters to investigate the effects of inlet flow rates, substrate rotation, and height of the reactor chamber. It is seen that for some combinations of the parameters the flow above the wafer is unsteady. Effect of rounded corners on damping instabilities of the shear layers is explored. By employing the rounded corners, we have been able to reduce the RMS non-uniformity to about 1% at atmospheric pressure on a 30 cm wafer. The impinging jet geometry can be used for the deposition of thin solid films without the penalty of a vacuum system and associated equipment costs. (C) 2004 Elsevier Ltd. All rights reserved.