Interaction of HCN/DCN with Si(100)-2X1

Article abstract of DOI:10.1021/j100129a026

We have investigated the spectroscopy and reaction of HCN (DCN) adsorbed on Si(100)-2X1 at T_S >= 100 K using HREELS, XPS, and UPS.HCN (DCN) formed dimers and/or polymers on the surface at 100 K and higher dosages ( D > 4 langmuirs).The HREEL spectrum obtained after warming 4.5-langmuir HCN dosed surface to 220 K resembles that obtained with a lower HCN dosage (D < 0.6 langmuir).Two major species, HCNH and CN, could be identified from this spectrum.The former species showed peaks at 160, 368, and ca. 400 meV for HC=NH, CH, and NH stretching vibrations, respectively, while the latter showed a peak at 263 meV due to the C<*>N stretching vibration.In the corresponding DCN experiment, the DC=ND stretching mode was observed at 124 meV.Annealing the sample at 560 K appeared to cause the reorientation of the CN radical from an end-on to a side-on adsorption geometry as evidenced by HREELS, UPS, and XPS analyses.At 600-800 K, the breaking of NH and CN bonds occurred on the surface.Above 1000 K, a mixture of silicon carbide and silicon nitride was formed after the complete dissociation of CH, NH, and CN bonds and the desorption of H species.