Accession Number : ADA266903


Title :   The Thermal Dissociation of NH sub 2 CHO (ND sub 2 CHO) on Si(100)-2x1


Descriptive Note : Technical rept. no. 20,


Corporate Author : EMORY UNIV ATLANTA GA DEPT OF CHEMISTRY


Personal Author(s) : Bu, Y ; Lin, M C


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a266903.pdf


Report Date : 21 Jul 1993


Pagination or Media Count : 27


Abstract : The interaction between NH2CHO(ND2CHO) and Si(100)-2xl has been investigated using HREELS, UPS and XPS. At 100 K, formamide molecules randomly adsorbed on the surface, but became ordered, likely with the 0-atom attached to the surface, as the 2 L NH2CHO dosed Si(100) surface was warmed to 220 K. At this temperature, the formation of some Si-H species is indicated by the appearance of the 256 meV peak due to Si-H stretching vibration in HREELS. When the sample was annealed at 450 K, the OH and more H species were formed. In addition, a peak at 172(160) meV appeared in HREELS, which could be attributed to the HN=C (DN=C) and/or HNCO (DNCO) species. The latter species is more clearly evident in the UP spectrum. At 550 K, the breaking of CH, NH and probably some OH bonds continued and the OH and H dominated the adspecies. Further annealing the sample at higher temperatures caused the formation of Si- O-Si complex as indicated by the 129 meV peak in HREELS due to the asymmetric stretching mode of the Si-O-Si species. Above 800 K, the Si-H stretching mode at 260 meV decreased dramatically because of the desorption of the H-species.


Descriptors :   *SURFACE CHEMISTRY , *FORMAMIDES , ANNEALING , VIBRATION , INTERACTIONS , MOLECULES , DESORPTION , ATOMS , X RAY PHOTOELECTRON SPECTROSCOPY , SILICON


Subject Categories : Physical Chemistry


Distribution Statement : APPROVED FOR PUBLIC RELEASE