EAGER: Design, Fabrication, and Testing of All-Metal-Terminal Hot-Electron Transistors (AMTHETs) for Multi-THz Operation

从理论上分析了一种新的晶体管结构，它具有放大频率高达或超过10太赫兹(THz)的信号的潜力，这比现有的硅晶体管的频率高出一个数量级以上。拟议的研究项目的目标是开展实验工作，以制造概念验证原型晶体管，并对这些晶体管的性能进行建模和表征，以便验证所提议的新型晶体管结构在极高频率下实现大于1的电流增益的潜力。提出的新型晶体管有可能使集成电路振荡器、放大器和混频器的频率达到或超过3THZ。它们有可能使用小型(手持)室温高能效装置对材料进行太赫兹光谱分析，用于安全(隐藏武器检测)和医学成像(牙科)应用。这些超快晶体管还提供了构建以时钟频率运行的数字电路的潜力，该时钟频率比完全缩放的CMOS技术实现的时钟频率快一个数量级。而且，这些超快晶体管还可以使数据转换器、光网络组件、高速通信电路和高速雷达系统的最大工作频率提高数量级。理论计算表明，全金属端子热电子晶体管(AMTHET)具有实现大于10的电流增益和工作在10 THz或更高频率的潜力。拟议研究项目的目标是验证和改进这些理论计算，并确定是否有必要对AMTHET进行进一步的研究工作。所提出的AMTHET是一种金属-半导体-金属-半导体-金属夹层，其中半导体层中主要载流子的平均自由程长于半导体层的厚度，中间金属层中电子的平均自由程长于中间金属层的厚度。这种结构形成了双极结晶体管(BJT)，其中发射极、基极和集电极是由EB和BC半导体层彼此隔开的金属层。我们建议使用两个结合在一起的绝缘体上硅(SOI)晶片来制造概念验证原型AMTHET，以形成硅-金属-硅层堆栈。随后将去除大部分SOI晶片并沉积金属以完成AMTHET结构。随着材料和几何形状的变化，这些原型器件的性能的低频和高频测量将被用于为AMTHET的建模和分析提供信息，并指导未来迭代的设计。将开发一种基于物理的AMTHET器件模型，适用于未来具有特定性能目标的AMTHET的设计，并与实验测量相吻合。这项工作有可能促进对双极晶体管的理解，在双极晶体管中，大多数电荷载流子直接从发射极传输到集电极，而不会发生散射。

A novel transistor structure has been theoretically analyzed that has the potential to amplify signals at frequencies up to and beyond 10 Tera-Hertz (THz), which is more than an order of magnitude higher frequency than possible with existing silicon transistors. The goal of the proposed research project is to carry out experimental work to fabricate proof-of-concept prototype transistors and to model and characterize the performance of these transistors in order to verify the potential of the proposed novel transistor structure to achieve current gain greater than unity at extremely high frequencies. The proposed novel transistor has the potential to enable integrated circuit oscillators, amplifiers and mixers at frequencies up to and above 3 THz. They have the potential to enable THz spectrographic analysis of materials using small (hand-held) room-temperature power-efficient units for security (hidden weapon detection) and medical imaging (dental) applications. These ultra-fast transistors also offer the potential to enable the construction of digital circuits operating at clock frequencies that are an order of magnitude faster than those achieved by fully scaled CMOS technologies. And, these ultra-fast transistors could also enable an order of magnitude increase in the maximum operating frequencies of data converters, optical networking components, high-speed communications circuits and high-speed radar systems.Theoretical calculations indicate that All-Metal-Terminal Hot-Electron Transistors (AMTHETs) have the potential to achieve a current gain of greater than 10 and to operate at frequencies up to or beyond 10 THz. The goal of the proposed research project is to verify and refine these theoretical calculations and to determine if further research work on the AMTHET is warranted. The proposed AMTHET is a metal-semiconductor-metal-semiconductor-metal sandwich in which the mean-free-path of the dominant carrier in the semiconductor layers is longer than the thickness of the semiconductor layers; and, the mean free path of electrons in the middle metal layer is longer than the thickness of the middle metal layer. This structure forms a bipolar junction transistor (BJT) in which the emitter, base and collector are metal layers separated from each other by EB and BC semiconductor layers. We propose to fabricate proof-of-concept prototype AMTHETs using two silicon-on-insulator (SOI) wafers bonded together to form the silicon-metal-silicon layer stack. This will be followed by removal of the bulk of the SOI wafers and deposition of metal to complete the AMTHET structure. Low-frequency and high-frequency measurements of the performance of these prototype devices as the materials and geometries are changed will be used to inform the modeling and analysis of AMTHETs and to guide the design of future iterations. A physics-based device model for the AMTHET, suitable for use in the design of future AMTHETs with particular performance targets, will be developed and fit to the experimental measurements. This work has the potential to advance understanding of bipolar transistors in which a majority of the charge carriers transit directly from the emitter to the collector without scattering.