Citation

Sault AG, Goodman DW. Surface Science 1990; 235(1): 28-46.

Copyright

(Copyright © 1990)

DOI

10.1016/0039-6028(90)90103-F

PMID

unavailable

Abstract

Reactions of silane with the W(110) surface have been studied using temperature programmed desorption, Auger electron spectroscopy and low energy electron diffraction. At 350 K, silane undergoes complete dissociation on the clean W(110) surface, with an initial dissociation probability of one. The hydrogen atoms produced by silane dissociation are displaced from the surface by silicon atoms during large silane exposures. As the silicon coverage increases, the silane dissociation probability remains ≥ 0.5 until a monolayer of silicon is deposited. The weak dependence of dissociation probability on silicon coverage suggests that dissociation occurs via a mobile precursor. Once the first monolayer is complete, the silane dissociation probability decreases sharply to less than 0.01. At 120 K, silane undergoes only partial dissociation. The resulting adsorbed species are tentatively identified as silyl (SiH3) groups. The silyl groups decompose during temperature programmed desorption at 200-300 K to evolve H2 and leave adsorbed silicon atoms on the surface. Adsorbed silicon atoms form a number of ordered overlayer structures, depending on both the silicon and hydrogen coverages and the temperature to which the overlayers are annealed. Heating silicon overlayers to 1050 K results in reaction between silicon and tungsten to form epitaxial tungsten suicide overlayers. Repeated cycles of silane adsorption followed by annealing to 1050 K result in the epitaxial growth of stoichiometric WSi2 layers on the surface. © 1990.

Language: en