Magnetron Sputtering Mnzn Ferrite Thin-film Technology Research

Because MnZn ferrite has high saturation magnetic induction, high permeability and low power loss, it has become the largest products of soft magnetic materials with a wide application. Due to the high resistance, high mechanical strength, chemical stability and high resonance frequency, this material can be used in high-frequency areas. As the electronic components become smaller, integrated as well as applied in high frequency, the research of MnZn ferrite films become a hot issue. Base on the above-mentioned trends, this dissertation use ratio-frequency magnetron sputtering to fabricate MnZn ferrite films. For the purpose of optimize the property of the films, the sputtering parameters, annealing process and buffer layer were investigated.The parameters of fabricating MnZn ferrite target were studied at the beginning of the dissertation. The formulation of MnxZn1-xFe2O(40≤x≤1)and sintering temperature were discussed. From the experiment result, the formulation of Mn0.5Zn0.5Fe2O4 and sintering at 1300℃are the best condition in creating a fine target.The sputtering pressure of Ar experiment shows moderate pressure (1.4Pa) can avoid the phenomenon of scattering from sputtering atom as well as improve the quality of the MnZn ferrite films. The sputtering power has a strong connect with the migration energy of sputtering particles, the result confirm that the sputtering yield is monotonically increasing when sputtering power rise up. When the sputtering power reaches 140W, the films have fine properties and good microstructure. The substrate temperature play an important part in crystallization of the films, the result verify that even at 50℃, the films get crystallization from the data of XRD. The films deposited on Si had different orientation from the glass substrate. After adding the oxygen, the sputtering yield obviously decrease, because of the interrupting in glow discharge, also the saturation magnetization fall as the oxygen added into sputtering atmosphere.Both the bell furnace and the vacuum chamber were used for annealing films. The result shows that vacuum chamber have better capability in controlling the annealing atmosphere. The saturation magnetization of the films decrease after annealing in vacuum chamber at 500℃, but the coercivity get improved. The buffer layer of ZnFe2O4 also was discussed both with annealing and without. It demonstrates the moderate thick of the buffer layer can improve saturation magnetization but the effect on coercivity is limited. When the buffer layer reach the thickness of 40nm, the films got a good qualification of Ms (297 kA/m) and coercivity (6.8kA/m).