SCHOTTKY BARRIERS AT EPITAXIAL SILICIDE/SI INTERFACES

We studied the electronic structure of the YSi2/Si(111) and NiSi2/Si(001) interfaces using the linear muffin-tin orbitals in the atomic sphere approximation (LMTO-ASA) based on the local density approximation (LDA). Together with the previous results on the CoSi2/Si(111) and NiSi2/Si(111) interfaces, we showed that LMTO-ASA calculations with a large supercell give an adequate Schottky barrier height (SBH: E(F)-E(V)) for real silicide/Si interfaces although the LDA depresses the band gap of bulk Si to almost half of the experimental value. An eightfold NiSi2/Si(001) interface showed almost the same SBH as the type A NiSi2/Si(111) interface. From the relation between the interface structure and the calculated SBH, we speculate that the bond angle at the interface affects the SBH.