Annealing temperature effects on the structure of ferromagnetic Mn-implanted Si

The dependence of the magnetization of Mn-implanted Si on the postimplant annealing temperature is studied. p -type Si wafers were implanted with 300 keV Mn+ ions at 350 °C to a fluence of 1× 1016 cm-2 and then annealed at 500-900 °C for 5 min. Ferromagnetic hysteresis loops were obtained at 10 K using a superconducting quantum interference device magnetometer. The saturation magnetization increases with the postimplant annealing temperature, reaching an optimum field strength of 0.2 emug at 800 °C. An out diffusion of Mn is observed at higher temperatures that coincides with a decrease in the saturation magnetization. The calculated point-defect profile that was generated by the implantation process peaks around the Mn-depleted region, suggesting that the residual implant damage may play a role in the ferromagnetic behavior of Mn-implanted Si.