HREELS, TPD and ESD study of electron‐induced decomposition of trimethylamine on Si(100) at 100 K

Abstract

AbstractThe effects of 600 eV electron irradiation on adsorbed layers of trimethylamine (TMA) on a Si(100) surface at 100 K were studied using high‐resolution electron energy loss spectroscopy (HREELS), temperature programmed desorption (TPD), electron‐stimulated desorption (ESD) and x‐ray photoelectron spectroscopy (XPS). Experiments were performed at monolayer and higher coverages. The ESD results obtained on physisorbed TMA indicate electron‐induced decomposition of the parent molecule. The HREELS data also show cleavage of NC bonds on the chemisorbed layer of TMA and deposition of CHx groups on the surface, which is also supported by a dramatic enhancement of hydrogen desorption at 960 K following electron irradiation. This multiple‐step process is supported by ESD signal decay curves obtained during electron irradiation. Following electron irradiation of TMA/Si(100), the intensity of low temperature TPD peaks corresponding to TMA fragments decreases; however, the intensity of the mass 2 peak increases dramatically compared with the un‐irradiated surface. This is indicative of electron‐induced associative desorption of molecular hydrogen. The HREELS data from monolayer coverage of TMA on Si(100) after electron irradiation suggests the removal of CHx groups from the adsorbate layer and deposition of carbon and hydrogen on the surface. In the absence of physisorbed layers there is no indication of electron‐induced desorption of TMA fragments. Copyright © 2005 John Wiley & Sons, Ltd.