Preparation And Physical Properties Of Mn And Co-doped SiC Diluted Magnetic Semiconductor Films

With the coming of information age,the higher demands for information processing and transmission and storage of integration are more and more increased.The Diluted Magnetic Semiconductor on behalf of the spin electronic appliance has been expected. SiC based DMS,with its excellent performance of semiconductor and property of magnetic material concerned by more people.SiC films doped with Manganese(Mn) and Cobalt(Co) were prepared by the RF-magnetron sputtering. The prepared films were annealed in a vacuum environment at 1200℃and 800℃.The annealing treatment time was 40 minutes. The Mn and Co-doped films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine stucture (XFAS). The magnetic property and photoluminescence were texted by physical testing systems(PPMS)and UV - visible light photometer.The transport property of the DMS film was studied by R-T and I-V Curves. The results show that:1. There exist a diffraction peak at 2θ=38.319°in the Mn and Co-doped SiC films.The diffraction peak is the strongest diffraction peak of 3C-SiC.So the structure is 3C-SiC lattice structure,the SiC lattice was distortioned by Mn and Co-doping.With the increasing of doping concentration,the diffraction peak moved from high to low angle.After annealing, the second phase Mn₄Si₇ and CoSi formed.2. By XPS and XAFS measurements, it can be found that the Mn and Co atoms were all doped into SiC lattice for the as-deposited and annealed SiC films, they were all two price. Co and Mn atoms were substituted enter the SiC lattice.The Mn-Si and Co-Si key were found in the annealed films.3. The I-V curve shows linear relationship,there were no metal cluster in the films.The metal-insulation films were not formed in Mn and Co-doped films.It shows that the films were un-homogeneous body system.With the temperature increased ,the R-T curve resistivity contours reduced.The semiconducting properties is obvious.4. The magnetic property test shows that Mn and Co-doped films have room temperature ferromagnetic.The saturation magnetization increased with the increasing of Mn content.The saturation magnetization was 15emu/cm³,When the Mn content was 9at%. With the annealing temperature increasing, the saturation magnetization of the film increased. The saturation magnetization increasing with the increasing Co content,from 1.9emu/cm³ to 6.5 emu/cm³ ,When the Mn content was 9at%,the saturation magnetization reduced to 2 emu/cm³ .The 800℃annealing temperature benefitsed to the magnetization of the films.Its saturation magnetization is 12emu/cm³.