Formation of light-emitting FeSi2 in Fe thin films on ion-implanted (111)Si

The formation of iron silicides on (111)Si and effects of ion implantation on phase transformation have been investigated by sheet resistance measurements, grazing-incidence x-ray diffractometry, transmission electron microscopy, energy-dispersive x-ray analysis, and secondary ion mass spectroscopy. Ion implantation was found to enhance the growth of light-emitting β-FeSi2. Phase transformation from FeSi to β-FeSi2 begins at 600 °C and completes at 700 °C. P+ implantation was found to lower the transformation temperature from 700 to 600 °C. Wider than 20 nm As-decorated grain boundaries were observed in the As+-implanted samples annealed at 600–700 °C. The As-rich grain boundaries disappeared after 800 °C annealing, leading to a decrease in resistivity.