Magnetic Properties And High Frequency Properties Of FeSiAl(N) Thin Films

The increasingly highly integrated trend of electronic industry has made more demands of the products with smaller dimension and higher performance at present.And the rapidly development of the information technology is eager for the improvement of the computational speed at the same time.In that case,the soft magnetic films with high saturation magnetization and high complex permeability applied to GHz range magnetic devices have been a hot area of research for several years.In this paper,we studied Fe Si Al films with excellent soft magnetic properties.Fe Si Al films were deposited onto a Si(100)substrate by radio-frequency(RF)magnetron sputtering and the Fe Si Al N films were deposited by RF reactive sputtering.The magnetic properties and structure were investigated by vibrating sample magnetometer(VSM),X-ray diffraction(XRD),scanning electron microscopy(SEM)and transmission electron microscopy(TEM)etc.The brief results are as follows,1.In our case,all the as-deposited Fe Si Al films are face-cubic-center(fcc)structure.And the films with sputtering pressure at 0.4 Pa and 0.8 Pa possess the minimum coercive force.The crystallinity of the as-deposited films increase with the increase of the thicknesses.2.The magnetic properties of obliquely sputtered single-layer Fe Si Al thin film show that the oblique sputtering method is a good method to induce fine in-plane uniaxial anisotropy.The anisotropy is mainly derived from the shape anisotropy generated by the so-called self-shadow effect when sputtering.Moreover,the resonance frequency of the oblique angle dependent is adjustable.When heating the substrate from room temperature to 435 K,the coercive force of the films decreases gradually and the anisotropic field induced by incident sputtering weakens at the same time.3.We studied the effect of the nitrogen flow changes on the eeactive sputterd Fe Si Al N film.It is found that a proper nitrogen dopant enhances the soft magnetic properties of Fe Si Al N films.It can provide higher saturation magnetization and lower coercivity,and also the electrical resistivity because of the formation of the granular structure at the same time.An increase of the damping factor has been detected,which would decrease the high frequency properties.4.We anneal the Fe Si Al N samples with a vacumn thermal treatment furnace.It shows that the annealing conditions have a great influence on the magnetic properties of the films.During the process,the strength of the induced anisotropic field is one of the most important factors to generate ferromagnetic resonance at GHz range.