基于宽带隙半导体的高性能TMIC带通滤波器设计与实现

Due to the disadvantages such as high packaging cost, low yield rate, and lack of reliability of the THz discrete systems, the system-level terahertz monolithic integrated circuits (TMIC) are considered to be the best solution for the implementation of terahertz systems. For this reason, research on the monolithic integration of passive devices such as filters and antennas at the ends of terahertz transceiver systems has extremely high value and an urgent need. Our project intends to design and implement high-performance terahertz monolithic integrated bandpass filters on wide band-gap semiconductor (WBS) materials using substrate-integrated waveguide (SIW) structural. SIW can solve not only the problem of difficult integration of terahertz cavity filters, but also the problem of high loss of the planar filter. It is also possible to use wide band gap semiconductor materials to improve the output power characteristics of the active part in the terahertz circuits, which improve the performance of the whole THz system. Through the microwave analysis and the research of wide band-gap semiconductor fabrication process, our project plans to achieve several THz monolithic integrated bandpass filter with high performance, fabrication compatibility and yield rate. Also, the project will providing theoretical basis and experimental support for feature design and fabrication of the system-level TMIC.

由于分立型太赫兹(THz)系统存在如封装成本高、良品率低、可靠性不足等诸多缺陷,系统级的太赫兹单片集成电路（TMIC）被认为是实现太赫兹系统的最佳方案。为此，对太赫兹收发系统末端，如滤波器，天线等无源器件的单片集成化研究有极高的价值和迫切的需求。本研究项目拟以基片集成波导(SIW)为元件，在宽带隙半导体(WBS)材料上实现高性能太赫兹单片集成滤波器的设计和加工。在利用SIW解决太赫兹频段腔体滤波器难以集成和平面滤波器损耗过大问题的同时，亦可利用宽带隙半导体材料改善系统有源部分的功率输出特性，从而整体提升THz系统的性能。项目将通过微波理论设计和宽带隙半导体工艺设计，实现多款性能好、工艺兼容性强、良品率高的太赫兹单片集成滤波器，同时也为未来太赫兹系统级单片集成电路的设计，加工提供充分的理论依据和实验支持。

项目开发了宽带隙半导体TMIC带通滤波器的完整工艺流程，并对关键的工艺如金属图形化、衬底粘接减薄、精细通孔刻蚀等进行了深度优化设计。明确了减薄参数对速率、均匀性及机械强度和粗糙度方面的影响，实现了碳化硅减薄速率在10μm/h至400μm/h可调。研究并开发了倾角可调的碳化硅通孔精确刻蚀工艺，实现了孔径30μm至130μm，深宽比0.5-4，倾角80°- 88°的碳化硅通孔。. 在工艺基础上，对单片集成波导在太赫兹频段的损耗机理进行了研究，并确定了工艺参数与器件性能的关系。提出了通孔有效直径，以改善仿真和实际测量的一致性。 基于优化参数设计并制造了一个基于碳化硅的基片集成波导，在140GHz～220GHz频率范围内，其测量的衰减常数低至 0.19dB/λg。进一步的，项目研究了太赫兹宽带隙半导体单片集成带通滤波器实现机理与参数调控方案，基于CT拓扑和过模腔体设计了一款太赫兹带通滤波器，通过对耦合系数和品质因数进行详细分析，解释了零点的产生和控制机理。滤波器在180 GHz时其插入损耗仅为1.5 dB, 体积仅为同类矩形波导滤波器的千分之一。同时，项目还基于多模理论和腔体形状控制，提出了集成耦合腔结构，配合矩形过模腔零点控制法，实现了通带两侧均有传输零点的高带外抑制窄带滤波器，其中心频率为185 GHz，左右两侧各存在2个传输零点，其相对带宽仅为3%，插入损耗也仅为3 dB。