Ferromagnetism dependence on hole carriers in polycrystalline silicon films co-doped with Mn and B

Polycrystalline Si0.96Mn0.04:B films were prepared by cosputtering deposition followed by rapid thermal annealing for crystallization. The films are ferromagnetic with Curie temperatures of about 250 K. Through the approach of microwave plasma enhanced chemical vapor deposition, the films were treated by hydrogen plasma and boron plasma. After the plasma treatments, the structural properties of the films did not change, while both the saturation magnetization and hole concentration in the films changed. The correlation between the magnetic properties and the transport properties of the Si0.96Mn0.04:B films suggests that free hole carriers play an important role in Si:Mn diluted magnetic semiconductors.