Influence of Oxygen on the Iridium Silicide Formation by Rapid Thermal Annealing

Iridium silicide formation by rapid thermal annealing (RTA) in an Ar atmosphere or under vacuum has been investigated. The evolution of the silicide front and the identification of the phases were monitored by Auger Electron Spectroscopy (AES) and Rutherford Backscattering Spectrometry (RBS). Oxygen was incorporated during the RTA process in an Ar atmosphere. The oxygen effect is to slow down the silicide formation and eventually to stop it. In all the cases, the oxygen piled-up at the iridium-iridium silicide interface. No distinguishable phase was formed by RTA in an Ar atmosphere. No oxygen contarsi'nation was detected when the RTA was performed under a vacuum lower than 2×10 −5 Torr. In this case Ir 1 Si 1 and Ir 1 Si 1.75 phases were formed.