Accession Number : ADA254643


Title :   Halogen Surface Chemistry on Si(100)-(2xl)


Descriptive Note : Technical rept.,


Corporate Author : PITTSBURGH UNIV PA DEPT OF CHEMISTRY


Personal Author(s) : Yates, John T , Jr ; Cheng, C C ; Gao, Q ; Choyke, W J


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a254643.pdf


Report Date : 02 Jul 1992


Pagination or Media Count : 24


Abstract : The surface chemistry of adsorbed halogen atoms on Si(100) has been studied using several surface science methods. It has been found using electron-stimulated desorption ion angular distribution (ESDIAD) that Cl atoms bond to dangling bonds on symmetric Si2 dimer sites, and that the Si-Cl bond angle is tilted (25 deg +/-4 deg) from the normal in the vertical plane containing the symmetric Si2 dimer bond. The covalently-bonded halogens Cl, Br, and I have been studied on Si(100) using atomic hydrogen bombardment at low substrate temperatures (300 - 630 K). In all cases, facile elimination of the hydrogen halide occurs, and the coverage of halogen may be driven to zero by moderate exposure to atomic hydrogen. The halogen extraction process is almost non-activated, suggesting that the chemical reaction to produce hydrogen halide species is driven by the potential energy carried by the atomic hydrogen species. This is an example of an Eley-Rideal reaction process and provides a potentially useful new approach for controlling atomic layer chemistry on semiconductors.


Descriptors :   *SILICON , *SURFACE CHEMISTRY , *CHLORINE , *HALOGENS , ANGLES , IONS , TEMPERATURE , DISTRIBUTION , CHEMICALS , LAYERS , SITES , ENERGY , THIN FILMS , SUBSTRATES , ATOMS , SEMICONDUCTORS , ETCHING , HYDROGEN , SURFACES , CHEMICAL BONDS , CHEMISTRY , APPROACH , DIMERS , ELIMINATION , DESORPTION , POTENTIAL ENERGY , EXTRACTION , HALIDES , SYMMETRY , CHEMICAL REACTIONS , ELECTRONS


Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Atomic and Molecular Physics and Spectroscopy


Distribution Statement : APPROVED FOR PUBLIC RELEASE