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

Abstract

The 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 CH x 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 CH x 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.

Electron Induced Surface Reactions of Organometallic Metal(hfac)2 Precursors and Deposit Purification

“…These observations explain why electron irradiation leads to significant losses of oxygen and fluorine atoms from the film, but only a comparatively small change in the carbon content. Although XPS cannot detect hydrogen atoms, the significant increase in intensity of the gas phase m / z = 2 peak (Figure a­(ii)) during electron irradiation indicates that hydrogen is lost from the film as H 2 (g) because of electron-stimulated C–H bond cleavage, a prominent reaction pathway for adsorbed hydrocarbons exposed to electron irradiation. − …”

Growth and Microstructure of Nanoscale Amorphous Carbon Nitride Films Deposited by Electron Beam Irradiation of 1,2-Diaminopropane

“…Thus, XPS and MS results collectively support the idea that dehydrogenation is the major chemical transformation that accompanies electron irradiation of molecularly adsorbed 1,2-DAP . Hydrogen has also been observed as the dominant gas phase product when surface bound amines , and organic films, including alkanes and self-assembled monolayers, − are irradiated by incident electrons ranging in energies from 5 eV to 2 keV.…”

Adsorption and Dissociation of a Bicyclic Tertiary Diamine, Triethylenediamine, on a Si(100)-2 × 1 Surface

“…Among the tertiary amines, trimethylamine (TMA) adsorption on Si(100) has been studied in some detail. This includes theoretical studies into the activation energy of N−C bond dissociation, 23 XPS studies of the dissociation products at elevated temperature, 26 thermal desorption following TMA dosed at 100 K, 29 and other aspects of the adsorption process. 30,31 To summarize this work, at room temperature TMA mostly forms a stable datively bonded species, and a minor channel leads to N−C cleavage.…”

“…Among the tertiary amines, trimethylamine (TMA) adsorption on Si(100) has been studied in some detail. This includes theoretical studies into the activation energy of N–C bond dissociation, XPS studies of the dissociation products at elevated temperature, thermal desorption following TMA dosed at 100 K, and other aspects of the adsorption process. , To summarize this work, at room temperature TMA mostly forms a stable datively bonded species, and a minor channel leads to N–C cleavage. Similar to TMA, triethylamine (TEA) is also an interesting tertiary amine capable of forming a stable datively bonded species on silicon.…”