InP基共振隧穿二极管太赫兹振荡器的设计与实现

利用InP基共振隧穿二极管（RTD）和加载硅透镜的片上天线设计实现了超过1 THz的振荡器。采用Silvaco软件对RTD模型进行仿真研究,分析了不同发射区掺杂浓度、势垒层厚度、隔离层厚度以及势阱层厚度等对器件直流特性的影响规律。对研制的RTD器件直流特性测试显示：峰值电流密度Jp为359.2 kA/cm²,谷值电流密度Jv为135.8 kA/cm²,峰谷电流比PVCR为2.64,理论计算得到的器件最大射频输出功率和振荡频率（fmax）分别为1.71 mW和1.49 THz。利用透镜封装的形式对采用Bow-tie片上天线和RTD设计的太赫兹振荡器进行封装,测试得到振荡频率超过1 THz,输出功率为2.57μW,直流功耗为8.33 mW,是国内首次报道超过1 THz的振荡器。     

基于共振隧穿二极管的近程太赫兹通信技术

太赫兹通信技术是实现6G愿景的关键底层技术之一,针对应用场景选择不同技术路线定制收发系统将是其发展趋势。RTD太赫兹收发模块具有室温、高频率、高灵敏度、易集成等特点,成为太赫兹通信技术领域的新星。通过介绍RTD太赫兹源、探测器及通信系统的工作原理和现状,分析了目前面临的效率及灵敏度提升挑战,并从器件和电路层面探讨和展望了可能解决方案和技术方向,为推动RTD太赫兹通信实用化提出思考。     

太赫兹共振隧穿二极管探测器研究进展及应用

太赫兹波独特的性质使其在物理学、生物学、医疗诊断、无损检测、无线通信等领域有着广阔的应用前景。共振隧穿二极管(RTD)是一种基于量子隧穿效应的半导体器件,利用其负微分电阻和直流非线性特性,可以分别实现太赫兹波的产生和探测,近年来获得越来越多的关注。基于RTD的太赫兹探测器具有可室温工作、体积小、易集成、灵敏度高等特点,使其在未来短距离、超高速的太赫兹无线通信及万物互联等场景具备优势。本文将重点介绍太赫兹RTD探测器的研究进展及其应用进展,并对后续技术发展进行展望。     

基于RTD 材料结构与参数的RTO 设计与模拟*

首先对THz 波源的共振隧穿二极管(RTD)设计中的关键问题,即从材料与结构出发,对如何提高 RTD 的截止频率和输出功率进行了分析研究,并利用WinGreen 软件,仿真设计出具有高振荡频率和输出功率的 RTD。在此基础上,采用RTD 的共振隧穿理论和缝隙天线的结构模型,利用PSpice 仿真软件构建了包含RTD 材料 与结构参数以及缝隙天线结构参数在内的完整太赫兹振荡器(RTO)的等效电路模型。振荡频率约为1.02THz,输出 功率约为88.2μW,本文工作为今后研究该类器件奠定了基础。     

利用共振隧穿器件制作太赫兹波源

太赫兹波是振荡频率在100GHz～10THz范围的电磁波,利用共振隧穿器件高频高速的特点,适宜制作此波段的振荡源器件。指出与其他类型的太赫兹源器件相比,共振隧穿型太赫兹波源器件具有体积小、重量轻、便于与控制电路集成以及易于进行调制等特点;此外,还适宜用Si透镜进行功率合成,增大其总发射功率。给出几种重要太赫兹共振隧穿器件的结构、制造工艺和器件性能,作为太赫兹技术领域的研究人员选择太赫兹波源器件的参考。     

微型化太赫兹集成器件的前沿技术进展

针对国际上太赫兹器件技术进展予以概括和分析,提炼出共振隧穿二极管、单向载流子传输光电二极管2种可行的小型化器件方案。在材料生长和器件结构方面分析了太赫兹波的产生原理和难点,在系统应用方面解释了短距离高速通信的实用案例。目前,采用共振隧穿二极管已实现2.5 Gbps速率的300 GHz无线通信演示实验,采用单向载流子传输光电二极管在该频点下实现了12.5 Gbps的无线通信实验。     

共振隧穿型太赫兹波振荡器设计

本文设计的RTD结构,采用目前最新的发射极渐变In含量(GE)结构和集电区隔离层与势垒层之间的高In过渡层(HITL)结构,同时对发射区和集电区进行重掺杂。发射极设计面积为1μm2至几μm2的情况下,通过基于非平衡格林函数法的量子输运模拟器WinGreen模拟,将势阱厚度从4.5nm降低到4nm,峰值电流密度JP从13mA/μm2达到43mA/μm2,输出功率从235μW达到2.625mW。阵列型RTO可实现功率合成,使RTO的功率再增加一个数量级,达到毫瓦甚至几十毫瓦。同时建立包含各种寄生参数的等效电路模型,通过PSPICE工具仿真,得到振荡频率可达1.78THz的仿真结果。     

InP基RTD特性的数值模拟研究

采用基于非平衡格林函数法(Non-equilibrium Green’s function,NEGF)量子输运模拟器WinGreen对InP基共振隧穿二极管(RTD)的输运特性进行了计算模拟,分析了Ga0.47In0.53As/AlAs以及富In组份势阱双势垒结构几何参数、散射参数、发射区和集电区掺杂浓度以及隔离层厚度对InP基RTD器件I-V特性的影响。模拟结果表明,采用富In组份的势阱有利于降低峰值电压,提高发射区掺杂浓度有利于增大峰值电流密度,而散射则会导致谷值电流增大,影响其负阻特性。     

液晶太赫兹光子学研究进展

液晶作为液态和固态之间的中间态,具有液体的流动性和晶体的各向异性,其指向矢灵活可调,从微波到紫外都有广泛应用。近年来液晶光子学在太赫兹波段展现出巨大应用前景,本文综述了基于液晶的太赫兹源、可调太赫兹器件和太赫兹探测器的研究进展,探讨了未来液晶太赫兹光子学的发展趋势,如新型铁电向列相、液晶拓扑在太赫兹领域的应用,多模式、多参量的太赫兹波按需产生、调制与探测等。     

太赫兹返波振荡器的应用及研究进展

太赫兹返波振荡器是一种功率高、宽带可调谐、可在常温下连续波工作的辐射源。本文介绍了太赫兹返波振荡器在太赫兹技术研究中的应用需求及其发展现状,说明返波振荡器在太赫兹技术研究中的重要作用和前景,并对太赫兹返波振荡器的最新动态、技术难点进行了分析,可供该种管型研究的参考。     

用于太赫兹探测的InP基异维肖特基二极管

异维肖特基二极管(HDSD)是一种具有三维金属-二维半导体结的特殊的肖特基势垒二极管。由于具有较小的结电容和串联电阻,HDSD在太赫兹探测中很有应用潜力。本文研制了InP基HDSD,据我们所知相关工作尚未被报道过。与GaAs基HDSD相比,可以预期InP基HDSD有着更好的性能,一方面因为更高的电子迁移率和二维电子气(2DEG)浓度,另一方面因为更小的肖特基势垒高度。通过交流测量得到的截止频率高于500GHz,表明InP基HDSD具有应用于太赫兹探测的潜力。     

Nine-state resonant tunneling diode memory

The authors demonstrate an epitaxial series combination of eight pseudomorphic AlAs/In_0.53Ga_0.47As/InAs resonant tunneling diodes (RTDs) grown by molecular beam epitaxy on InP. This series RTD produces an eight-peak multiple negative differential resistance characteristic with a peak-to-valley current ratio (PVR) exceeding 2 per peak at a peak current density of approximately 6 kA/cm ². Hysteresis in the current-voltage characteristic is reduced by uniformly Si doping the double-barrier resonant tunneling region at a density of 5×10¹⁶ cm^-3. Using this multiple-peak RTD in series with a field-effect transistor load, a nine-state multivalued memory circuit is demonstrated     

共振隧穿二极管的设计和研制

用分子束外延在半绝缘砷化镓上生长两垒一阱结构,制成RTD单管。经过材料生长设计、工艺设计和版图设计几方面的改进,测得最高振荡频率已达54GHz。     

面向太赫兹应用的InP基肖特基二极管

Based on characteristics such as low barrier and high electron mobility of lattice matched In_0.53Ga_0.47 As layer,InP-based Schottky barrier diodes（SBDs） exhibit the superiorities in achieving a lower turn-on voltage and series resistance in comparison with GaAs ones.Planar InP-based SBDs have been developed in this paper.Measurements show that a low forward turn-on voltage of less than 0.2 V and a cutoff frequency of up to 3.4 THz have been achieved.The key factors of the diode such as series resistance and the zero-biased junction capacitance are measured to be 3.32Ωand 9.1 fF,respectively.They are highly consistent with the calculated values.The performances of the InP-based SBDs in this work,such as low noise and low loss,are promising for applications in the terahertz mixer,multiplier and detector circuits.     

Detection of terahertz radiation by resonant tunneling nanoheterostructures

The phenomenon of terahertz radiation detection by resonant tunneling structures (RTSs) has been studied. The calculations of the changes ΔI₀ in the direct current (DC) component I₀ under the action of an alternating electric field were carried out by the solution of a nonstationary Schrodinger equation with a time-periodic electric field based on the Floquet mode expansion of the wave functions. The dependences of the DC component I₀ in resonant tunneling structures on the frequency ν and AC signal amplitude V_ac have been built. It is shown that the ΔI₀ value in triple-barrier RTSs at resonance frequency hv ≈ E_r2–E_r1 (E_r1 and E_r2 are the energies of the size-quantized levels) can exceed a low-frequency value by more than an order of magnitude. The parameters of the structures have been optmized, in order to use them in the terahertz radiation detectors in the anbsence of an external bias. The possibility of tuning the resonance frequency in the terahertz range by changing the DC bias has been shown.     

Microwave detection using the resonant tunneling diode

An experimental and theoretical study in the use of a resonant tunneling diode (RTD) as a microwave detector, based on its small-signal equivalent circuit model, is presented. It is shown that the rectified current from the diode can be accurately predicted and that the diode can be operated as a reactive microwave detector which absorbs no microwave power. For this detection mode, a matching network which maximizes the applied AC voltage can be used     

Pspice resonant tunneling diode models and application circuits

Using the analogue behavioural modelling capabilities of Pspice, the current–voltage characteristics and the large-signal equivalent circuit of a resonant tunneling diode are exploited to create a Pspice compatible model for the diode. The model is used, with very few other components, in the simulation of a number of circuit applications, including a sinusoidal wave generator, a frequency multiplier and three state logic circuits. The simulated circuit details, the related waveforms and three-state logic operations are described. The circuits are characterized mainly by their reduced complexity and ease of analysis.     

An improved multipeak resonant tunneling diode model for nine-stateresonant tunneling diode memory circuit simulation

A simple Spice equivalent circuit model for simulating current-voltage (I-V) characteristics and logic operation waveforms of an eight-peak resonant tunneling diode is presented. The simulated results agreed well with experimental data measured from an eight-peak resonant tunneling diode device fabricated by Seabaugh's experiment. This is shown through PSpice simulation