Effect of annealing temperature on the ferromagnetism of Co-implanted silicon

Si1−xCox magnetic semiconductors were prepared by implanting 200 keV Co ions into p-type Si(1 0 0) wafer at room temperature, followed by 600-900 °C annealing. Room temperature ferromagnetism was observed in all samples and saturation magnetization was enhanced after 900 °C annealing, for which nano-sized (several nm to 50 nm) CoSi2 precipitates were present. It was found that the formation of CoSi2 phase could play an important role in the enhancement of ferromagnetism.