The thin film reactions—Mg 2Si and VSi 2

Abstract

Subsequent to the deposition and annealing of either V or Mg on Si, the reaction to form VSi 2 or Mg 2Si was analyzed using the following: X-ray diffraction to detect compound formation, AES to locate the two suicide interfaces, and SIMS to follow the diffusive separation of the natural abundance of Mg isotopes in the compound. The SIMS data show that the more massive Mg isotopes are found further from the Mg/Mg 2Si interface. Such an observation is consistent with Mg being the mobile isotope in the reaction and with grain boundary diffusion being the dominant kinetic mechanism of film growth. Silicon isotope separation was not found for either reaction; however, silicon is not mobile in Mg 2Si formation so separation is not expected. The thickening kinetics for both reactions is parabolic.