Reserarch On Film Preparation And Gamma Radiation Effect Of MnZn Ferrite Film

With the development of aerospace,both home and abroad start to research the film radiation stability, analyze the failure mechanism of device under radiation, find the ways to improve the radiation resistance. Mn Zn thin film belongs to spinel structure, with high saturation magnetization Ms and other characteristics, the introduction of Mn Zn film in the device will reduce the volume of the device, which promote the development of small and lightweight device. By studying the preparation of Mn Zn thin film technology, finally prepared thin film with excellent performance. The Mn Zn film can be more flexible application in the inductor, transformer, magnetic recording materials and other microelectronic devices. Thin film materials under the influence of radiation in aerospace environment will be different from the bulk materials. Because of the Mn Zn film has the nano-scale particles, this will greatly affect the components reliability, device life, etc. Gamma radiation will produce defects inside the materials, the microstructure and magnetic properties of Mn Zn thin film will be affected under the gamma radiation. It is great significant for Mn Zn thin film applied in aerospace, by studying the effect of different doses and different dose rate gamma radiation on the performance of the Mn Zn film.First of all, the thesis starts with the technology of film preparation, studying several important process parameters of the radio frequency(rf) magnetron sputtering system(power, pressure, substrate types, substrate temperature) on the influence of Mn Zn film performance. The results show that preparation of thin film under the sputtering power 160 W, appropriate sputtering pressure 0.6 Pa, single crystal Si(100) substrate has better microstructure and magnetic properties. The magnetization can be reached 192 k A/m, this film can be used for subsequent annealing and radiation research.Next, studying the influence of film under atmospheric pressure annealing and vacuum annealing, the results show that after vacuum annealing, thin film magnetic can be greatly improved, in vacuum the optimal annealing temperature is 550℃. Simulation study the film grain growth kinetics under vacuum annealing in different thermal time. The results show that under the temperature 550℃, thermal time(0-30 min) in vacuum annealing, the film TPRE grain growth kinetics equations is as follows:/106.5exp(43.903.9GRTKt Gn′-=-Finally, studying the different total doses and different dose rate effects of gamma irradiation on the properties of Mn Zn thin films. The research results show that: the film magnetization, the lattice constant, the grain size decreases with the increase of the total dose of gamma irradiation, under 25×104 Gy gamma irradiation, the magnetization decreased, the lattice constant decreased, the grain size decreased, the surface roughness increased. Study of different dose rate irradiation, under 38 Gy/min gamma irradiation, the film magnetization decreased 3%; under 152 Gy/min gamma irradiation, the film magnetization decreased 33.3%. The reason is because the gamma radiation on the thin film γ+Fe2+â†'Fe3++e–(Fe2+=0.76 ?,Fe3+=0.64 ?), leading to the change of lattice structure and magnetic properties, while the changes of microscopic surface is radiation damage due to collision with the surface gamma ray.