Initial Stages of Metal/Semiconductor Interface Formation: Au and AgON Si(111)
CALIFORNIA UNIV LOS ANGELES DEPT OF CHEMISTRY AND BIOCHEMISTRY
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We have studied the atomic structures formed by monolayer coverages of Au and Ag on the Si111 surface using primarily the technique of Impact- Collision Ion Scattering Spectroscopy ICISS. For the case of Au films annealed at 700 C, three different types of LEED patterns are formed depending on the fractional monolayer coverage 5x1, sq. root of 3 x sq. root of 3, and 6x6. The ICISS data reveal that all the three surfaces are structurally similar the Au atoms reside above the Si111 plane, most likely in threefold-hollow sites, and the different surfaces appear to be characterized by rows 5x1 or a honeycomb network sq. root of 3 x sq. root of 3 and 6x6. In contrast, the Ag films deposited at elevated substrate temperature 480 C display only a sq. root of 3 x sq. root of 3 LEED pattern for coverages ranging from 0.25 to 35 monolayers. A trimer model appears to be more consistent with the low coverage Ag ICISS data rather than a honeycomb arrangement of the Ag atoms.
- Physical Chemistry
- Atomic and Molecular Physics and Spectroscopy
- Solid State Physics