DAVYDOV SPLITTING AND RIGID-LAYER MODES IN INS CRYSTAL

Polarized infrared reflection spectra of InS layer crystal have been measured. Both components of the Davydov doublets caused by the splitting of intralayer vibrations due to the interlayer interactions are active in i.r. spectra. Doublet frequencies have been used to calculate the rigid-layer mode frequencies which are correlated with the experimental ones. It has been established that in InS crystal the frequencies of rigid-layer modes are much higher than those of ordinary layer crystals. Atomic displacements have been found at i.r.-active normal modes

The Co/Si(111) interface formation: a temperature dependent reaction

We have investigated the reaction of Co with the Si(111) surface both at room temperature (RT) and at high temperature (500-650 degreesC). The temperature evolution of the RT deposited 10 ML film has also been studied. The films, prepared by the different methods, have been structurally characterized by means of primary-beam diffraction modulated electron emission. Auger electron spectroscopy has been used to follow their stoichiometric evolution. For RT deposition the films have been found to have a B-type (180degrees rotated with respect to the underlying Si(111) surface) cubic structure with a Co content and an interlayer spacing increasing with thickness. After 650 degreesC annealing, the films are completely reacted and have an unstrained B-type CoSi2 structure. High temperature (500 degreesC) deposition of Co leads to the formation of stoichiometric CoSi2 films. Both annealed and high temperature grown films are found to be Si terminated

Initial stages of cobalt disilicide formation on silicon single crystals

The initial stages of cobalt disilicide formation on Si(111) and Si(100)surfaces are studied using backscattered electron imaging of the near-surface atomicstructure. Both the reactive deposition and the solid phase epitaxy are investigatedin the coverage range of 1-10 ML of Co. The evidence for CoSi2 island formation atthe earliest stages of the process is found. The epitaxial orientations of disilicidelayers grown on Si(111) and Si(100) surfaces are determined