低温烧结M型钡铁氧体高频软磁特性及应用研究

【作者】 刘东；

【导师】 刘颖力；

【作者基本信息】 电子科技大学 ， 电子科学与技术， 2010， 硕士

【摘要】 随着电子信息产业的飞速发展,电路模块及器件的小型化,集成化及高频化成为衡量该行业发展水平的重要标准。低温共烧陶瓷LTCC技术完全迎合现代电子系统高频化、小型化的发展要求,目前它已成为电子元件集成封装的关键技术,而相应的材料研究对LTCC技术的发展起至关重要的作用。由于M型钡铁氧体具有较大的矫顽力和磁能积、单轴磁晶各向异性等优点,因而被广泛的应用在永磁、吸波和微波毫米波器件等领域中。本论文主要围绕M型钡铁氧体的低温烧结及其在LTCC技术中的应用这一主题展开。在材料研究方面,首先对应用在微波领域的M型钡铁氧体进行了研究,通过钴钛掺杂提高了该材料的高频软磁特性,采用sol-gel工艺制备了钴钛掺杂M型钡铁氧体粉体。重点研究了掺杂量、烧结温度以及助烧剂BBSZ对钴钛掺杂的M型钡铁氧体材料磁性能参数的影响。通过研究发现,助烧剂BBSZ能够促进晶粒生长,降低粉体的烧结温度;钴钛离子的掺杂能够提高M型钡铁氧体材料起始磁导率,改善材料的高频软磁特性。通过大量实验研究,主要在提高起始磁导率、改善频率特性、降低烧结温度方面取得进展,成功研制了起始磁导率为14,烧结温度为920℃,截至频率为800MHZ应用于高频片式电感的M型钡铁氧体粉体。在片式器件研究方面,首先对M型铁氧体的流延工艺进行了研究,研制了性能较佳的M型铁氧体的流延膜片,确定了M型钡铁氧体在LTCC应用的工艺可行性。在有限元计算和电磁场仿真的理论指导下,借助HFSS软件进行片式电感、滤波器结构的优化设计及性能的仿真预测。用本文研制的低温烧结的Co/Ti掺杂钡铁氧体材料,按照仿真设计的片式元器件参数,在电子科技大学LTCC工艺生产线上进行了实际研制。经验证,实际制备的高频高感值片式电感,电感值为1μH,其感量比仿真预测值偏低,这主要是由于铁氧体的磁导率与标样环有一定差异缘故所造成。实际制备的低通滤波器,截止频率为400MHZ,带外抑制在2GHZ时大于25dB,其截止频率略高于仿真预测值,这主要是受LTCC工艺参数的精确控制较为困难的影响。更多还原

【Abstract】 The rapidly developing of electronic and information technology calls for the circle components and modules being miniaturized integrated and high frequency all of this has become the crucial standard of the evaluating the development of this industry. Low Temperature Co-firing Ceramic (LTCC) technology being one of the best candidates to obtain these requirements so naturedly the study of the materials used in LTCC technology is important even to the whole electronic industry. And the M-style barium ferrite having the large coercive force magnetic energy produce and uniaxial magnetocrystalline anisotropy is widly studied in many fields including permanent magnetic material wave absorption material and microwave and millimeter wave devices. So in this article our work is largely focus on the application of M-style barium ferrite in LTCC technology is studied.In the materials aspect the performance of Ba-ferrite in microwave is taken in consideration. The Co and Ti substituted ferrite is fabricated by sol-gel process the measurement shows that the substitution increase the soft magnetic performance of this material in high-frequency. And the study of how the doping amount sintering temperature and sintering agent BBSZ effect the magnetic characteristics of M-style Ba-ferrite is carried out which shows that the sintering agent will benefit the growth of grain bring down the sintering temperature and the doping of Co and Ti will increase the initial permeability of the Ba-ferrite and also improve the soft magnetic behavior in high frequency. We have fabricated the M-style Ba-ferrite with initial permeability being 14 cut-off frequency being 800MHz which can be applied in high frequency multilayer chips inductor.In the multilayer chips components aspect we have studied tape casting process and confirmed the feasibility of M-style Ba-ferrite applicated in LTCC technology. Utilizing HFSS we obtained the optimized parameters of the multilayer chips inductors and filters. Then the samples of these inductors and filters were fabricated using the LTCC production line in UESTC. The measurements show that the inductance of the inductor sample is 1μH a little lower than the simulation one which is thought to be caused by the difference of permeability between the ferrite and standard sample. On the other hand the filter sample with cut-off frequency being 400MHz out band rejection larger than 25dB in the frequency 2GHz reason of the higher cut-off frequency is thought to be the processing parameters in LTCC are hard to be controlled.更多还原