The (001) surface of silicon has been the topic of our study in
this thesis. The clean surface, an-adatom or submonolayer
adsorption on the surface, the monolayer adsorption and its
stability conditions as well as growth simulation on the surface
were investigated using the state of the art techniques.
We have used ab initio density functional calculations
based on norm-conserving pseudopotentials to investigate the Mg adsorption on the Si(001) surface for 1/4, 1/2 and 1 monolayer (ML) coverages. For both 1/4 and 1/2 ML coverages it has been found that the most favorable site for the Mg adsorption is the cave site between two dimer rows consistent with recent experiments. For the 1 ML coverage (2 Mg atoms per 2X1 unit cell) we have found that the most preferable configuration is when both Mg atoms on 2X1 reconstruction occupy the two shallow sites. We have found that the minimum energy configurations for 1/4 ML coverage is a 2X2 reconstruction while for the 1/2 and 1 ML coverages they are 2X1.
Same method was also used to investigate the surface stress and energetics of the clean-, Sb-adsorbed-, and
Sb-interdiffused-Si(001) surface. It is found that interdiffusion
of Sb into deeper layers of Si(001) leads to a more isotropic
surface stress but corresponds to a higher total energy
configuration. As a result of competition between stress relief
and energy gain, the surface with all the Sb atoms adsorbed on top of Si(001) surface layer is predicted to have a less ordered geometry and roughness in z-direction. We have repeated the similar calculations on the Ge(001) surface for comparison.
Finally using empirical molecular dynamics method, we have
investigated the crystalline growth of silicon on Si(001) as a
function of substrate temperature and incident particle energy.
Our results show that the increase of substrate temperature
enhances the crystallinity in the film grown on the Si(001)
surface, on the other hand, the crystalline growth can be enhanced at low temperature by using higher incidence energy.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12604904/index.pdf |
| Date | 01 April 2004 |
| Creators | Shaltaf, Riad |
| Contributors | Ellialtioglu, Sinasi |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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