Ruthenium silicide (Ru2Si3) films were fabricated by an inter-layer reaction between ruthenium and silicon, and their oxidation resistance was investigated. These films remain conductive even after oxidation at 700 degreesC, which is more than 100 degreesC higher than that in the case of a TiN film. When a Ru/Ru2Si3/Si structure is heat-treated at 700 degreesC, the ruthenium film reacts with the silicon that diffused through the Ru2Si3 layer from the substrate, and forms Ru2Si3. On the other hand, if the Ru2Si3 layer is oxidized at 600 degreesC in advance and then the ruthenium film is deposited, further silicidation in the Ru/Ru2S3/Si structure can be suppressed. This is because a 2 nm thick amorphous oxide layer formed at the Ru/Ru2Si3 interface suppresses the diffusion of silicon. However, the oxide layer causes the contact resistance of the Ru/Ru2Si3/Si structure to increase. (C) 2003 Elsevier Science B.V. All rights reserved.