A study has been made of the Row, heat and mass transfer with chemical reactions and thermophoretic transport with application to external chemical vapor deposition processes. The system includes a jet that is emerging from a burner containing fuel (methane), oxygen, nitrogen and silicon tetrachloride which react and form silica soot particles. The flow impinges on a disk which serves as the target for the depositing material. The motion of the particles is determined from the combined effects of thermophoresis, buoyancy and the forced Row leaving the burner. The governing conservation equations, which include the effects of buoyancy, variable properties, chemical reactions and thermophoretic transport have been solved numerically. The effects of the burner location and the disk diameter on particle deposition are studied. The local and average particle deposition, the variation of the deposition efficiency and the heat Aux are determined over a range of values of the parameters.