Stress-development mechanism during cobalt-silicide film formation

The silicidation-induced stress developing during Co-silicide formation was discussed experimentally. Co films deposited on Si substrates were annealed to form the silicide films. The formation of CoSi and CoSi₂ started at about 400°C and 600°C, respectively. The stress-development mechanism in the reacted films was discussed based on the measurement results of both the internal stress and the thermal stress of Co, CoSi and CoSi₂ films. Silicidation-induced stress was defined as the difference between the measured internal stress after the silicidation and the assumed internal stress which was calculated by extending thermal stress curve before silicidation. The silicidation-induced stresses were about 300 MPa for CoSi formation and about 500 MPa for CoSi₂ formation.