Thermal decomposition of a metal-organic chemical vapor deposition precursor, (t-BuN)2W(–NEt2)2, (bis(tertbutylimido)bis(diethylamido)tungsten, on Si(100) has been studied by means of synchrotron radiation-based x-ray photoemission spectroscopy and temperature programmed desorption spectroscopy. The resultant thin films consist of tungsten metal, silicon carbides and silicon nitrides. Major desorption products originated from ligand decomposition include imine (C2H5NCHCH3) that is derived from β-H elimination of diethylamido ligand, and isobutene (C4H8) that is generated from γ-H elimination of t-butylimido ligands. The transmetalation of the precursor leads to tungsten metal adsorption on Si(100); by contrast, tungsten nitrides, tungsten carbides and tungsten oxides are produced as the same precursor is decomposed on SiO2 surface. © 2003 American Vacuum Society.