Ti掺杂TaN薄膜与微波衰减器研究

发布时间：2018-03-18 15:46

  本文选题：衰减器　切入点：TaN薄膜　出处：《电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：微波衰减器因其质量轻、体积小、易集成、使用频率高等特点而被广泛应用于现代微波通信系统和微波电路中。衰减器在微波系统中主要作用是调节输入信号电平且不使信号发生畸变。微带薄膜衰减器主要通过电阻性薄膜材料吸收功率转化为热量来实现衰减。Ta N薄膜作为重要的电阻性薄膜材料,具有非常重要的研究价值。本文首先研究了Ta N薄膜材料的性能,并将Ta N薄膜作为电阻材料设计了一系列不同衰减量的衰减器。本文关于微波衰减器主要做了以下三方面的研究工作:在材料方面,通过在Ta靶上放置不同面积的Ti靶来实现不同比例的Ti掺杂,研究了Ti掺杂比例对Ta N薄膜电阻率和电阻温度系数(TCR)的影响。研究发现随着Ti掺杂比例的增大,薄膜的电阻率逐渐增大,但薄膜的TCR也逐渐增大。当掺杂比例达到26%时,Ta N薄膜的电阻率几乎增加了一倍,薄膜的TCR也由未掺杂时的-45 ppm/℃增大到-214 ppm/℃;通过控制流入真空室中N2的含量来制备多层膜结构,多层膜由Ta、Ti构成的金属层和Ta N、Ti N构成的氮化层组成。研究发现随着Ta、Ti构成的金属层比例不断增大,薄膜的电阻率逐渐减小,但薄膜的TCR也逐渐减小,当金属层的比例增大到67%时,薄膜的TCR由-166 ppm/℃变为-74 ppm/℃,TCR得到改善。在衰减器设计与仿真方面,根据多级衰减器级联的思想,利用HFSS软件设计仿真了衰减量分别为12 d B、13 d B、19 d B、20 d B(两种)共五种衰减器。其使用频率均为DC-15GHz,在该频率范围内,VSWR均小于1.25。依据电阻膜面积大小,设计12 d B衰减器和13 d B衰减器的承载功率为2W,19 d B衰减器和20 d B衰减器(两种)的承载功率为3W。在衰减器制作与测试方面,利用磁控溅射,真空蒸发和光刻等技术在被釉Be O基片上制备了衰减器;制作测试夹具,利用矢量网络分析仪测试了衰减器的微波性能,测试结果基本与设计相符。通过对各个衰减器加载1小时相应的设计功率,测得电阻膜表面最高温度都低于125℃,达到了设计要求。
[Abstract]:Microwave attenuator is easy to integrate because of its light weight, small volume and easy integration. It is widely used in modern microwave communication system and microwave circuit because of its high frequency. The main function of attenuator in microwave system is to adjust the input signal level without distorting the signal. As an important resistive thin film material, the attenuation can be realized by converting the absorption power of resistive thin film into heat. In this paper, the properties of Ta N thin films are studied. A series of attenuators with different attenuations are designed using Ta N thin films as resistive materials. In this paper, the microwave attenuators are studied in the following three aspects: in material, The effects of Ti doping ratio on resistivity and TCRs of Ta N thin films are studied by placing Ti targets with different areas on Ta targets. It is found that the ratio of Ti doping increases with the increase of Ti doping ratio. The resistivity of Ta-N thin films increases gradually, but the TCR of the films increases gradually. When the doping ratio reaches 26, the resistivity of Ta N thin films almost doubles, and the TCR of the films increases from -45 ppm/ 鈩，

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