Study On Preparation And Electromagnetic Properties Of Fe₃Si/Insulator/Si Multilayer Films

Fe₃Si/Insulator/Si multilayer films are prepared by magnetron sputtering system and vacuum annealing furnace.The thickness of the MgO layer was controlled to 20 nm,50 nm,100 nm,150 nm,and 200 nm by controlling the sputtering time.The film thickness ratios of Fe and Si were 2:1,2.5:1,3:1,3.5:1,and 4:1,respectively.Annealing temperatures were600℃,650℃,700℃,750℃,800℃,850℃,900℃and the annealing time was 3 hours.Samples with different Fe,Si ratios,different MgO thicknesses,and different annealing temperatures were prepared by orthogonal experiments.The crystal structure and microstructure of Fe₃Si thin films were studied by X-ray diffraction（XRD）and scanning electron microscopy（SEM）.At the annealing temperatures of600℃,650℃and 700℃,Fe_0.9Si_0.1.1 thin films were formed regardless of the thickness of MgO layer.When the annealing temperature is 750℃and the thickness of MgO layer is 20nm,50nm,100nm and 150nm,Fe_0.9Si_0.1.1 thin film is formed on the sample.the thickness of MgO layer is 200nm,the ratio of 2:1 to 2.5:1 results in the formation of Fe₃Si film,but the orientation of Fe₃Si is disorderly in the（110）phase.The diffraction peaks of sample Fe₃Si are obvious at the film thickness ratios of 3:1 and 3.5:1,and the film formation quality is better.When the film thickness ratio is 4:1,the diffraction peak of（200）phase of sample Fe₃Si does not form a sharp peak,and the film formation quality of the sample is poor.When the annealing temperature is 800℃,Fe₃Si is formed in the sample and silicide FeSi is generated,but a single layer is formed when the MgO layer thickness is 100 nm and the MgO layer thickness is 150 nm and the film thickness ratio is 3.5:1.Phase of Fe₃Si film.Higher quality Si-rich FeSi₂ films were formed at 850℃20nm and 900℃200nm,which can provide reference for the preparation ofβ-FeSi2 devices.The results are different from those without the buffer layer.When there is no buffer layer,the Fe_0.9Si_0.1.1 thin film is formed when the annealing temperature is below 700℃,and Fe₃Si is generated along with the annealing temperature of 700℃.When the annealing temperature is 800℃or above,the sample will produce FeSi thin film.The single-phase Fe₃Si film produced at 800℃100nm 3:1 has the best quality,the resistivity of the film is 0.011Ω·cm,and the flat band capacitance of the sample CV characteristic is about 9.37pF.