Image Number 4 for United States Patent #6683356.
A semiconductor device includes sidewall insulating films formed on sides of the gate electrode layer respectively facing source and drain regions, and silicide layers formed on the source and drain regions. Oxygen-introduced portions are respectively formed in the source and drain regions near the sidewall insulating films. The oxygen-introduced portions contain oxygen atoms that are locally distributed on the interfaces between the silicide layers and the silicon layers of the source or drain regions at a concentration of 4.5.times.10.sup.19 cm.sup.-3 or more and an areal density of 5.times.10.sup.13 cm.sup.-2 or more. The oxygen-introduced portions form an Ohmic contact between the silicide layers and the silicon layers of the source or drain regions.