The formation of Ni silicides on Si1 - yCy (y = 0.01 and 0.018) epilayers grown on Si(001) has been investigated. The presence of C atoms was found to significantly retard the growth kinetics of NiSi and enhances the thermal stability of thin NiSi films. For Ni(11 nm)/Si 0.982C0.018 samples, the process window of NiSi was shifted and extended to 450-700 °C. Moreover, there was an additional strain introduced into the Si1 - yCy epilayers during Ni silicidation. This work shows the potential of Ni silicidation on Si 1yCy for device applications.