Investigation of Metal-Semiconductor and Heterojunction Devices at Tarahertz Frequencies

这个研究项目将研究电子 异质结构器件中的输运， 提高太赫兹频率性能 半导体器件. 三种特殊类型的两个- 将研究终端设备;金属 半导体结、异质结势垒 二极管和高电子迁移率二极管。 金属- 半导体结一直是 毫米波和亚毫米波器件 应用多年，并继续产生 在太赫兹频率下的最先进性能。 我们在这些设备上继续工作的目标 将提高工作频率， 10 THz范围并确定基本极限 最大工作频率。 的 异质结势垒器件将使用势垒 在两种III-V半导体材料之间， 控制电流垂直于 接口. 由于组合物和掺杂的 半导体材料可以在很宽的范围内变化 范围内，屏障的性能可以达到 度，以产生所需的设备 针对特定应用的特性。 的 异质结势垒变容管是一种新型 该设备有望大大改善 最大频率和频率输出功率 乘数，将被广泛研究。 随着时间 允许，异质结势垒对 金属-半导体结也将 研究，通过改变设计的 异质结的重要性质， 二极管可以控制，从而大大提高 设计灵活性和更高的性能。 的 高电子迁移率二极管是一种全新 双端器件，其中电子 传导是在二维电子气中， 异质结界面。 我们以前的NSF 格兰特领导了一个原型高- 电子迁移率变容二极管， 强非线性电容-电压 特性和大的反向击穿电压。 对本补助金中研究的每种器械的研究 将有三个具体组成部分; 基础器件物理学研究 研究拟议装置的可行性， （二） 科学应用和制造 原型设备，以评估理论 预测。

This research program will investigate electron transport in heterostructure devices with the goal of improving the performance of terahertz-frequency semiconductor devices. Three specific types of two- terminal devices will be investigated; metal semiconductor junctions, heterojunction barrier diodes, and a high-electron mobility diode. Metal- semiconductor junctions have been the workhorse device in millimeter and submillimeter wavelength applications for many years, and continue to yield state-of-the-art performance at THz frequencies. The goals of our continued work on these devices will be to increase the operating frequency to the 10 THz range and determine the fundamental limit to their maximum operating frequency. The heterojunction barrier devices will use the barrier between two III-V semiconductor materials to control the current flow perpendicular to the interface. Since the composition and doping of the semiconductor materials can be varied over a wide range, the properties of the barrier can, to a degree, be tailored to yield the desired device characteristics for specific applications. The heterojunction barrier varactor which is a novel device that promises to greatly improve the maximum frequency and output power of frequency multipliers, will be extensively investigated. As time permits, the effect of a heterojunction barrier on a metal-semiconductor junction will also be investigated, by varying the design of the heterojunction, the important properties of the diode can be controlled, leading to greatly increased design flexibility and improved performance. The high electron mobility diode is a fundamentally new two-terminal device in which the electron conduction is in a two dimensional electron gas at the heterojunction interface. Our previous NSF grant led to the investigation of a prototype high- electron mobility varactor diode that exhibited strongly non-linear capacitance-voltage characteristics and large reverse breakdown voltage. Research on each device investigated in this grant will have three specific components; the investigation of fundamental device physics, the study of the feasibility of the proposed device for (2) scientific applications and the fabrication of prototype devices to evaluate the theoretical predictions.