IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Wednesday Sessions
       Session SS2-WeM

Paper SS2-WeM6
Abstraction of Si and SiH@sub x@ (x=1,2,3) Adsorbed on Cu(100) Surfaces with Gaseous D towards Silane

Wednesday, October 31, 2001, 10:00 am, Room 121

Session: Surface Reactions on Metals
Presenter: D. Kolovos-Vellianitis, EPIII, University of Bayreuth, Germany
Authors: D. Kolovos-Vellianitis, EPIII, University of Bayreuth, Germany
Th. Kammler, Focus GmbH, Germany
Th. Zecho, University of Bayreuth, Germany
J. Kueppers, University of Bayreuth, Germany
Correspondent: Click to Email
The study of metal-silicide interfaces is of significant imterest because of their important technological applications. In particular, a better understanding of the formation of silicon structures on metal surfaces using chemical vapor deposition (CVD) of silane and disilane can provide valuable information about the elementary processes of adsorption, dissociation and reaction with other gaseous atoms. The interaction of silane and disilane with Cu(100) surfaces was studied in the temperature range 77 K to 650 K with thermal desorption and Auger electron spectroscopies. Silane admission to Cu(100) at low temperatures initially leads to a complete decomposition of the silanes into adsorbed Si and H. Close to saturation of the surface with H, SiH@sub x@ species remain intact on the surface. They were identified as SiH@sub 3@ and to a smaller extent SiH@sub 2@ by monitoring the silane abstraction products and their kinetics during admitting gaseous D to the surface between 77 K and 200 K. Silane desorption through recombination of SiH@sub 3@ and SiH@sub 2@ with adsorbed H occurs around 157 K and 224 K, respectively. After hydrogen desorption around 300 K a Si covered surface remains, which can be converted to a clean Cu(100) surface by activating Si bulk diffusion around 700 K. Adsorbed Si is abstracted from the surface below 200 K by gaseous H via formation of silane through a sequence of 4 hydrogenation steps. The first hydrogenation reaction is rate determining and is significantly accelerated by increasing the temperature between 77 K and 200 K. Above 200 K a thermally unstable SiH@sub x@ species blocks the abstraction reaction. The reaction kinetics phenomenology is in accordance with an Eley-Rideal scenario.