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A combination of experimental and computational studies presents direct proof of a novel reaction pathway that delivers aromatic compounds onto a Si(100)-2 x 1 substrate. Benzylazide chemisorbs on a Si(100)-2 x 1 surface, and this chemisorption is followed by nitrogen elimination, leading to a stable surface adduct based on a Si-Si-N cyclic entity. This reaction occurs via a stable surface intermediate with the surface-bound nitrogen molecule stabilized by the presence of a neighboring aromatic group, which eventually releases nitrogen into the gas phase and forms the final product.

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Surface chemistry of nitroethane on Si(100)-2 × 1 has been investigated using multiple internal reflection Fourier transform infrared spectroscopy (MIR-FTIR), Auger electron spectroscopy (AES), and thermal desorption mass spectrometry. Molecular adsorption of nitroethane at submonolayer coverages dominates at cryogenic temperatures (95 K). As the surface temperature is increased to 140 K, chemical reaction involving nitro group occurs, whereas the ethyl entity remains intact. Similar behavior is observed for nitromethane. Thus, a barrier of approximately 36 kJ/mol is established for the interaction of nitroalkane molecules with the Si(100)-2 × 1 surface in contrast to the essentially barrierless transformation predicted previously theoretically for nitromethane. Further annealing of the silicon surface leads to the decomposition of nitroethane. The concentration of nitrogen and oxygen remains constant on a surface within the temperature interval studied here, whereas approximately half of the ethyl groups undergo hydrogen elimination, which releases ethylene and produces surface hydrogen. The rest of the ethyl groups decompose leading to the formation of surface carbon as confirmed by AES.

Multiple internal reflection Fourier transform infrared spectroscopy, together with other analytical techniques, was used to follow the diffusion of atomic hydrogen through a 10-nm-thick titanium carbonitride layer deposited onto a Si(100)-2x1 surface from tetrakis(dimethylamino)titanium as a chemical vapor deposition precursor. The recombinative desorption of hydrogen from the TiCN/Si interface was shown to coincide with the temperature range where most Ti-based diffusion barriers break down.