The effect of oxygen on the formation of manganese silicide

The behavior of oxygen impurities during thermal annealing of manganese-silicon diffusion couples and reactive deposition of MnSi1.7 films has been studied. Samples were prepared by reactive deposition or thermal evaporation of manganese on silicon (100) substrates, which were then annealed in vacuum. The investigation techniques included depth profiling using Auger electron spectroscopy and electrical resistance measurements. The oxygen contamination originated from the preparation chamber or exposing the sample to air before thermal annealing. The oxygen diffused into the manganese film and blocked the silicide formation. For reactive deposition of the MnSi1.7 films, the competition between silicide formation and oxygen diffusion resulted in the formation of silicide films with oxygen concentration of about 5 at% or the diffusion of oxygen in the manganese film with oxygen concentration of about 35 at%. The presence of a higher concentration of oxygen in the manganese layer prevented any silicide formation.