【作者】 杨瑞朝；

【导师】 于军；

【作者基本信息】 华中科技大学 ， 微电子学与固体电子学， 2009， 硕士

【摘要】 相控阵天线用铁电薄膜移相器具有速度快、驱动功率小、功率容量大、可靠性好、抗辐射性好及成本低等优点,是目前各国军事机构和科研机构研究的热点之一。本文研究了铁电薄膜移相器平面波导（ CPW ）结构的传输特性、移相器用Ba_1-x-yPb_xSr_yTiO₃（BPST）材料的制备与表征以及移相器单元的设计和制备工艺等。根据准静态场法和全波分析法分别得出了CPW结构特征阻抗解。利用MATLAB软件分析了模型结构参数对特征阻抗的影响,利用HFSS软件对CPW结构和电容加载CPW结构进行了模拟仿真和参数优化。给出了移相器单元设计的优化参数:信号线宽度40μm⁶0μm;缝隙宽度10μm²0μm;BST薄膜厚度0.5μm¹μm;铂电极厚度为4.6μm以上,金电极厚度为2.2μm以上;加载叉指电极的叉指宽度2μm ⁵μm,叉指间距2μm ⁵μm,叉指长度35μm。设计了BPST材料体系,利用固态烧结工艺制备了BPST靶材,利用射频磁控溅射法制备了BPST薄膜。通过对薄膜样品的XRD分析和介电性能测试,得出BST薄膜制备的优化工艺参数:衬底温度为600℃,溅射气压为2Pa,溅射气氛为O2:Ar =1:5,此条件下制备的BST薄膜介电常数为455,介电损耗为0.0143,调谐率为34%,FOM因子为23.77;得出BPST薄膜制备的优化工艺参数为:衬底温度为400℃,溅射气压为2Pa,溅射气氛为O2:Ar =1:5,此条件下制备的BPST薄膜介电常数为520,介电损耗为0.017,调谐率为48%,FOM因子为28.24。由以上结果得出,Pb掺杂改良了BST薄膜材料的介电性能。利用半导体工艺制备了相应的铁电薄膜移相器单元。采用剥离工艺制备了移相器单元和叉指阵列单元电极,电极图形最小线宽为1.5μm。更多还原

【Abstract】 The ferroelectric films based shifter for phase array antenna using has attracted much more attention in recent years because it has merits such as rapid scanning, small drive power, high power capability, anti-radiation, high reliability and low cost. In this dissertation, the transmission characteristics of coplanar waveguide structure of ferroelectric films based shifter, preparation and characterization of Ba_1-x-yPb_xSr_yTiO₃ materials for phase shifter using, design and fabrication of phase shifter unit are discussed.According to quasi-static field method and the full-wave analysis method the characteristics impendence solution of CPW structure are derived separately. The effection of structure parameters on device impendence is analysed by using MATLAB software. The simulation and optimization of CPW and CPW with capacitance loaded model parameters are implemented using HFSS software. The optimization parameters of phase shifter model are derived as the width of signal line is 40μm to 60μm, the width of slot is 10μm to 20μm, the thickness of BST film is 0.5μm to 1μm, the thickness of Pt electrode is over 4.6μm, the thickness of Au electrode is over 2.2μm, the width of interdigital electrode as capacitance loaded is 2μm to 5μm, the width between interdigital electrode is 2μm to 5μm, the length of interdigital electrode is 35μm and the best substrate material is MgO, LaAlO3 and high resistance Si.The series of BPST materials are designed. BPST ceramic targets are prepared by solid state sintering method. BPST films are prepared by RF-magnetron sputtering. According to the result analysed by XRD and dielectric properties test, the optimization parameters of RF-magnetron sputtering preparation technology for BST films are derived as the temperature of substrate is 600℃, the spurting pressure is 2 Pa and the sputtering atmosphere is O2:Ar as 1:5. The dielectric constant of BST film prepared in technology above is 455, the dielectric loss is 0.0143, the tunability is 34%, the FOM is 23.77. The optimization parameters of preparation technology for BPST film are derived as the temperature of substrate is 400℃, the spurting pressure is 2 Pa and the sputtering atmosphere is O2:Ar as 1:5. The dielectric constant of BPST film prepared in technology above is 520, the dielectric loss is 0.017, the tunability is 48%, the FOM is 28.24. Based on the results above it is indicated that Pb doping improves the performance of BST film.The ferroelectric films based phase shifter unit is fabricated using semiconductor technology. The phase shifter units and interdigital electrode array are fabricated by lift-off technology and the smallest width of electrode is 1.5μm.更多还原