GAS-PHASE DECOMPOSITION REACTIONS OF TRIS(DIMETHYLAMINO)PHOSPHINE, TRIS(DIMETHYLAMINO)ARSINE, AND TRIS(DIMETHYLAMINO)STIBINE REAGENTS

Gas-phase pyrolysis of tris(dimethylamino)phosphine (DMAP), tris(dimethylamino)arsine (DMAAs), and tris(dimethylamino)stibine (DMASb) relevant to organometallic chemical vapor deposition (OMCVD) has been investigated using fiber-optic-based Fourier transform infrared spectroscopy and molecular beam mass spectrometry. Gas-phase decomposition studies in Hz, D-2, and He reveal that the primary pathway is homolysis of the E-N (E = P, As, Sb) bond, leading to the formation of dimethylaminyl radicals. The pyrolysis proceeds according to a first-order process, with activation energies of 50.6, 44.0, and 41.1 kcal/mol for DMAP, DMAAs, and DMASb, respectively. Subsequent interactions of dimethylaminyl radicals result in the formation of the stable products: methylmethyleneimine, dimethylamine, methyleneimine, and methane. At temperatures higher than 550 degrees C, the dimethylaminyl radical decomposes with the generation of ammonia and methane as primary products in hydrogen.