新型AlGaN/GaN异质结横向结构MSM-2DEG变容管器件和太赫兹倍频电路研究

高频大功率太赫兹源是THz收发系统的关键部件。基于肖特基二极管技术的THz倍频器具有全固态、易集成等优点，是电子学THz源的重要研究方向。GaN材料具有击穿电压高、耐高温等优势，在实现大功率源方面被寄予希望。但受困于GaN的低电子迁移率，GaN基SBD的截止频率表现不理想，一直难以实现高频倍频器。本项目拟基于申请人自主设计并研制的高截止频率AlGaN/GaN异质结横向MSM-2DEG变容管，开展基于新器件的高频GaN倍频器研究。研究横向肖特基金属对沟道2DEG的耗尽规律，提高变容管的电容非线性；建立横向MSM-2DEG变容管的三维电磁模型和集总元件模型，解析新结构器件中电阻、电容、旁路寄生以及高阶参数的耦合关系，为倍频器设计提供高精度模型基础；结合器件对称C-V特点，开展奇次倍频电路设计，探明横向MSM-2DEG变容管的电路设计方法，最终研制出超过300GHz高频大功率GaN基倍频电路。

High frequency and high power terahertz (THz) sources are expected for solutions to close the "THz gap", as well as for emerging terahertz applications in communication, remote sensing, spectroscopy, radioastronomy, and pollution monitoring. All-solid-state and uncooled THz multiplier chain is one of the most important THz sources, in which Schottky varactor devices are the critical nolinear up-conversion devices. The wide bandgap GaN material with high breakdown field, high thermal conductivity and high electronic saturation rate can be considered as an excellent candidate to realize the high-power source, because of the power handling capability of GaN. .However, due to the low electron mobility of GaN materials, the cut-off frequency characteristics of GaN-based SBD devices are not ideal, and the GaN-based frequency multipliers with high operating frequency has been unable to be realized. Aiming at the above problems, the applicant design and fabricate the novel lateral-structure MSM-2DEG varactors with high cut-off frequency based on AlGaN/GaN heterostructures. The objective of this proposal is to develop GaN-based multipliers with high operating frequency. This project intends to the study on the depletion law of 2DEG channel in the lateral schottky structure, so as to improve the capacitance nonlinearity and cut-off frequency characteristics of varactor devices. The three-dimensional electromagnetic simulation model and lumped element model of lateral-structure MSM-2DEG varactors will be carefully developed to resolve the coupling effects between resistance, capacitance, bypass parasitism and high-order parasitic parameters. With high-precision model foundation, the circuit design are able to realize multipliers with higher frequency and efficiency. Combined with the symmetrical I-V and C-V characteristics, the circuit design method of the odd harmonic frequency multipliers will be studied in detail based on the AlGaN/GaN heterostructure lateral-structure MSM-2DEG varactors with high cut-off frequency. Finally, the high-frequency and high-power GaN-based frequency multipliers will be fully fabricated. And their operating frequency and output power performance will be demonstrated.