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

Abstract

The dependence of the magnetization of Mn-implanted Si on the postimplant annealing temperature is studied. p-type Si wafers were implanted with 300keV Mn+ ions at 350°C to a fluence of 1×1016cm−2 and then annealed at 500–900°C for 5min. Ferromagnetic hysteresis loops were obtained at 10K using a superconducting quantum interference device magnetometer. The saturation magnetization increases with the postimplant annealing temperature, reaching an optimum field strength of 0.2emu∕g 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.