GHz磁集成薄膜及滤波器的研究

发布时间：2018-11-27 19:02

【摘要】：集成电路等电子设备中的传导模式的电磁干扰(EMI)已成为当前国际上的热点问题之一,消除集成电路和晶体管等有源器件和系统中电磁干扰的最有效的办法,是研制磁集成薄膜EMI滤波器。集成小型化的薄膜EMI滤波器的首要任务是把截止频率fr提高到GHz频段,并使磁性薄膜保持优良的软磁性能和高频性能。由于材料是器件的基础,所以软磁薄膜的高性能、宽频段和低损耗是集成磁芯器件获得高性能的关键。针对应用于GHz范围的集成抗EMI滤波器,磁性薄膜必须满足高频段的应用需求,也就是说,其截止频率fr必须达到GHz范围,具有高的磁导率和低的损耗角正切tgδ。根据应用需求的不同,磁性薄膜的电磁性能和高频性能必须可调控。基于对软磁薄膜明确的性能要求,本论文以CoNbZr软磁薄膜为磁芯研究对象,优化设计了共面波导(CPW),集成制作了GHz滤波器,可应用于电磁干扰的抑制。首先,采用射频磁控溅射的方法在Si基片上沉积了CoNbZr软磁薄膜,主要研究了溅射膜厚、溅射功率、溅射气压、溅射倾斜角度等工艺参数,对薄膜高频性能和磁性能的影响。研究发现,溅射功率为250W,溅射气压0.4Pa,薄膜厚度140nm时,薄膜性能最优。其易轴矫顽力(Hce)为14Oe,面内各向异性场(Hk)为98Oe,饱和磁化强度(4πMs)高达15.9KGs,自然共振频率(fr)为3.5GHz,另外,倾斜角度的增大,可以够提高薄膜的Hk和fr,但同时也会导致Hce的增加和磁导率的减小。同时分析了工艺参数对薄膜磁性能影响的微观机理与物理机制。然后,采用高频仿真软件(HFSS)设计了共面波导(CPW)的尺寸,通过传统电镀工艺完成其制作。所得共面波导,在300kHz~20GHz的测试范围内,其传输损耗|S21|不超过0.4dB,满足阻抗匹配条件。另外,仿真设计了CoNbZr薄膜与CPW集成的滤波器,通过在磁性薄膜平面内施加一定角度的磁场,在10GHz-40GHz范围内可形成多频点窄带带阻滤波器。最后,采用微电子光刻技术,制作了应用于抗EMI的GHz磁芯集成滤波器。该滤波器是将CoNbZr薄膜集成在我们所设计的CPW上,通过磁性薄膜对噪声信号进行吸收衰减。在不加偏置角磁场时,器件的吸收频率为3.75GHz,衰减幅度-8.3dB。并且分析了器件的损耗机理,认为磁性薄膜的铁磁共振损耗是主要因素。
[Abstract]:Conductive mode electromagnetic interference (EMI) in electronic devices such as integrated circuits has become one of the hot issues in the world, and the most effective method to eliminate electromagnetic interference in active devices and systems such as integrated circuits and transistors. Magnetic integrated thin film EMI filter is developed. The primary task of the integrated miniaturized thin film EMI filter is to improve the cutoff frequency fr to the GHz band and to keep the magnetic thin film with excellent soft magnetic properties and high frequency performance. Because the material is the basis of the device, the high performance of the soft magnetic film, broadband band and low loss are the key to the high performance of the integrated magnetic core device. For integrated anti-EMI filters applied in GHz range, the magnetic films must meet the application requirements of high frequency band, that is, the cut-off frequency fr must reach the GHz range, with high permeability and low loss angle tangent tg 未. The electromagnetic and high frequency properties of magnetic thin films must be adjustable according to the application requirements. Based on the clear performance requirements of soft magnetic thin films, this paper takes CoNbZr soft magnetic thin films as the core research object, and optimizes the design of coplanar waveguide (CPW), integrated GHz filters, which can be applied to the suppression of electromagnetic interference. Firstly, CoNbZr soft magnetic thin films were deposited on Si substrates by RF magnetron sputtering. The effects of sputtering film thickness, sputtering power, sputtering pressure and sputtering tilt angle on the high frequency and magnetic properties of the films were studied. It is found that the film has the best performance when the sputtering power is 250 W, the sputtering pressure is 0.4 Pa, and the film thickness is 140nm. The easy axis coercivity (Hce) is 14Oe, the in-plane anisotropic field (Hk) is 98Oe, the saturation magnetization (4 蟺 Ms) is up to 15.9KGs, and the natural resonance frequency (fr) is 3.5GHz. In addition, the increase of tilt angle can increase the Hk and fr, of the films. But it also leads to the increase of Hce and the decrease of permeability. At the same time, the microcosmic and physical mechanism of the influence of process parameters on the magnetic properties of the films were analyzed. Then, the size of coplanar waveguide (CPW) is designed by high frequency simulation software (HFSS). In the range of 300kHz~20GHz, the transmission loss of the coplanar waveguide is less than 0.4 dB, and the impedance matching condition is satisfied. In addition, the filter integrated with CoNbZr film and CPW is designed by simulation. By applying a magnetic field at a certain angle in the plane of the magnetic film, a multi-frequency narrow-band stop-band filter can be formed in the range of 10GHz-40GHz. Finally, GHz core integrated filter for anti-EMI is fabricated by using microelectronic lithography technology. The filter integrates the CoNbZr film on the CPW designed by us and absorbs and attenuates the noise signal through the magnetic film. Without bias angle magnetic field, the absorption frequency of the device is 3.75 GHz and the attenuation amplitude is -8.3 dB. The loss mechanism of the device is analyzed and the ferromagnetic resonance loss of the magnetic film is considered as the main factor.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN713

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