Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MM: Metall- und Materialphysik
MM 9: Interfaces
MM 9.2: Vortrag
Montag, 27. März 2006, 15:00–15:15, IFW D
Structure and reactivity at the Ti-Si boundary — •Sibylle Gemming1,2, Andrey Enyashin1,2, and Michael Schreiber2 — 1Physikalische Chemie und Elektrochemie, Technische Universität, D-01062 Dresden. — 2Institut für Physik, Technische Universität, D-09107 Chemnitz.
The density-functional band-structure investigation of several supercell models for the Ti(0001)|Si(111) interface reveals that an atomically flat interface is quite unstable due to the large lattice mismatch between the two constitutents. The most realistic supercell model with a remaining strain of 1% yields a very low interface energy of only 0.28 J/m2 with respect to fracture into the two unrelaxed surfaces. This adhesion is mainly due to an interfacial electron transfer from Ti to Si. Other possible model structures with higher local strains are even non-bonding, which indicates the pronounced influence of the elastic interactions. Density-functional molecular dynamics at an elevated temperature of 600 K, however, shows, that a silicide interlayer is formed at the interface, which significantly strengthens the interface and doubles the interface energy. Further investigations on the interfaces between Ti or Si and the reaction product TiSi2 confirm, that the silicide layer at the interface is beneficial for the mechanical stability of the contact.