YSi 2-x films were grown by ion-assisted evaporation in an ultrahigh vacuum (UHV) on Si(111) through a thin SiO 2 layer. The films grown on the oxidized Si were changed from a polycrystalline structure with various phases of oxides and silicides into a single-crystalline silicide structure as the annealing temperature was increased in the UHV chamber. The structural change with the annealing temperature implied that various Y 2O 3 phases formed by the reaction between Y and SiO 2 were decomposed and transformed into YSi 2-x under the UHV environment. Rutherford backscattering spectroscopy/channeling showed that, although the interfacial crystallinity of the film grown on the SiO 2 layer was poorer quality than the film grown on a clean Si surface, a single crystalline YSi 2-x layer with high crystallinity (χ min=8%) was grown. These results showed that the difference of the thermal energy and the formation energy between the oxides of Y 2O 3-SiO 2 and yttrium silicide determined the evolution of the silicide layer formation and its crystal structure.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)