Although hot wall multiwafer reactors are preferred today for various applications, there are several hardware limitations. The current work uses a new reactor design which allows operation of the scavenger zone at an elevated temperature which can attain the same temperature as the process temperature setting of 900 degrees C. A two-dimensional axisymmetric dopant transport analysis using a plug flow approximation for velocity showed that the dopant concentrations at the free stream and near the wafer surface are almost equal implying insignificant dopant depletion in the reactor. The same conclusion is arrived at from the actual total dose in the wafers which is <5%. Temperature is therefore the most critical factor for process control which is validated by the improved reactor performance. A simple one-dimensional diffusion analysis of phosphorus in silicon was very useful in predicting the diffusion coefficient fairly accurately. Henry’s constant is computed to be 6.5E+7 for phosphorus on silicon substrate with P2O5 as the gas phase and P/Si as the other. A better estimate for the diffusion coefficient of phosphorus in silicon has been made which ranges from 2.353-14 cm(2)/s to 2.9E-14 cm(2)/s whereas literature gives a wider range, 1E-15 cm(2)/s to 4E-14 cm(2)/s. Measurement errors introduced from secondary ion mass spectroscopy technique, temperature calibration, surface oxide can contribute to the absolute value of the predicted diffusion coefficient. The empirical reaction rate of P2O5 vapor with solid polysilicon, K, was found to be 0.375 cm/s which predicts the average phosphorus concentration in polysilicon fairly accurately.