Mn-silicide nanoparticles formed inside Si using ion implantation

300 keV Mn was implanted into p-Si with a fluence of 1*10ˆ15/cm2, 1*10ˆ16/cm2 and 5*10ˆ16/cm2, respectively, at 620 K. The samples were annealed at 1070 K in N2 ambient for 5 min by rapid thermal annealing. Rutherford backscattering/channeling, transmission electron microscopy and X-ray diraction were applied for structural characterization. Mnsilicide nanoparticles were formed with the size of 5 nm already in the asimplanted samples and grew up to around 30 nm after annealing. Moreover no significant evidence is found for Mn substituting Si sites either in as-implanted or annealed samples. The virgin samples already show a ferromagnetic like behavior, and the moment is slightly increased after implantation (1*10ˆ16/cm2) and annealing by around 0.5 Bohr magneton per Mn. Therefore, the majority of Mn ions formed Mn-silicides, and some are diluted in Si matrix and develop into ferromagnetic coupling. These effects have to be properly considered for the design of Si-based diluted magnetic semiconductors.
[1] M. Bolduc, C. Awo-Aouda, A. Stollenwerk, M. B. Huang, F. G. Ramos, G. Agnello, and V. P. LaBella Phys. Rev. B 71, 033302 (2005).