The chemical reactions of WF6 and SiH4 with reactive ion sputtered TiN surfaces have been studied in ultrahigh vacuum. Auger electron spectroscopy was used in situ to study the surface reactions from 300 to 550-degrees-C. The effects of O and C surface contamination due to atmospheric exposure are characterized and comparisons are made to substrates sputter cleaned in vacuo. The WF6 + TiN reaction exhibits linear growth rates over the range of temperatures studied. TiN surface oxidation reduces the initial WF6 reaction probability from approximately 0.8 to <0.1, and increases the effective activation energy from 0.04 to 0.62 eV. Surface C has no effect on the reaction. A simple kinetic model is presented that describes the uptake of W on either clean or oxidized TiN surfaces. The exposure of TiN to SiH4 results in the deposition of Si with a reaction probability of approximately 10(-4). Auger peak shapes indicate that Si is bonded to 0 on oxidized TiN surfaces and elementally or as SiN on sputter cleaned TiN. When the TiN was exposed first to WF6 the SiH4 reaction probability for subsequent exposure increased to 0.06.