The oxidation behavior at the sidewall of patterned TiSi2/polysilicon gate stack has been studied at temperatures from 700 to 850 degreesC. Oxidation above 800 degreesC caused an abnormally enhanced oxidation of TiSi2 sidewall, which was not observed in unpatterned TiSi2/polysilicon stack, regardless of the oxidation atmosphere. High-resolution transmission electron microscopy study showed that a SiO2-TiO2 mixture was produced during the enhanced oxidation of TiSi2 film. Lightly doped drain structures with TiSi2/polysilicon gate and nitride spacer were fabricated using gate reoxidation at 750 degreesC without degradation of sheet resistance.