基于人工非线性电磁媒质谐波特性的固态电学单片太赫兹波研究

Terahertz (THz) technology is known as one of the top ten technologies to change the future world and it is an important crossover frontier research area. Over the years, the development of THz technology is severely limited due to the lack of effecicient electrical THz wave. The nonliear metamaterial (left-handed nonlinear transmission line) will be introduced to the THz field in this project, where THz GaAs heterostructure barrier varactor (GaAs HBV) is used as the nonlinear component in the THz left-handed nonlinear transmission line. The study on THz left-handed nonlinear transmission line will be carried out, and a new method to generate THz wave based on its frequency multiplication effect will be explored. The main contents are as follows: 1.propose the structure of planar THz GaAs HBV active device and THz passive device, which are adapted to the THz left-handed nonlinear transmission lines; 2.study the manufacture process and model extraction program of THz GaAs HBV; 3.explore the propagation characteristics of THz wave in the left-handed nonlinear transmission line; 4.establish design and manufacture programs of the monolithic frequency multiplier based no the THz left-handed nonlinear transmission lines, and generate above 0.2 THz solid-state electronics THz wave. The study of this project is expected to provide related theoretical basis and technical support for generating the solid-state electronics THz wave based on the left-handed nonlinear transmission lines, and to promote the development of related applications of THz technology in china.

太赫兹（THz）技术被称为“改变未来世界十大技术”之一，是一个重要的交叉前沿研究领域。长期以来，高效电学THz源的缺乏，限制了THz技术的长足发展。本项目拟将人工非线性左手媒质（左手非线性传输线）应用于THz领域，开展以THz砷化镓异质结势垒变容管（GaAs HBV）为非线性元件的THz左手非线性传输线研究，探索基于其倍频效应产生单片电学THz波的新方法。主要研究内容如下：提出与THz左手非线性传输线相适应的新型平面结构THz GaAs HBV有源器件和THz 无源器件结构；研究THz GaAs HBV制备工艺和模型提取方案；探索THz波在左手非线性传输线中的传播特性；建立THz左手非线性传输线单片倍频器的设计和制作方案，产生0.1-0.2THz固态电学单片THz波。本项目研究有望为左手非线性传输线技术方案的电学THz波产生提供相关理论基础与技术支持，推动我国THz技术相关应用领域的发展。

本项目对太赫兹（THz）异质结势垒二极管（HBV）器件设计制作和以其为非线性元件的THz 左手非线性传输线（LH NLTLs）三倍频电路开展了相关研究。分别研究了THz HBV的器件工作原理、外延材料结构、器件制备工艺、模型提取、THz LH NLTLs谐波发生机理、THz LH NLTLs设计制造等。提出了一款适用于0.2-0.3THz LH NLTLs的3 GaAs/AlGaAs势垒、30µm2有源区面积、对称C-V特性的HBV；实现了零偏电容11.8fF、最大电容比6.6、击穿电压大于20 V、寄生串联电阻12.6 Ω、14V偏执电压下最大漏电流40 nA的高性能变容二极管。对LH NLTLs的奇异色散特性进行了理论分析，利用背对背结构组态肖特基二极管合成足有对称C-V特性的变容管，并以该组态结构的二极管为非线性元件设计制作了W波段LH NLTLs，对其谐波发生机理进行了深入实验研究，通过对比实验定量地研究了变容管有源区面积、左手并联电感和LH TLs色散结构（平衡和非平衡结构）等LH NLTLs结构参数与三次谐波输出频率和功率之间的关系，揭示了提高THz LH NLTLs三次谐波频率和输出功率的规律；利用单片微波集成电路工艺，制作了零偏电容21.2 fF、寄生串联电阻5.6 Ω、器件击穿电压20V的高性能背对背结构二极管，实现了99 GHz 9.9 dBm最高输出功率、4.5%转换效率、20.2% 3dB带宽的W波段THz LH NLTLs。最后以研制成功的THz HBV器件为非线性元件，利用上述谐波发生机理和色散特性，设计制造了0.3THz LH NLTLs三次谐波发生器，产生267 GHz 15.9 dBm最高输出功率、8%转换效率、23.6% 3dB带宽的三次谐波，完成项目预期研究目标。本项目研究为左LH NLTLs方案的固态电学THz波产生提供了相关理论基础与技术支持，有效推动了我国THz技术相关应用领域的发展。