Beta-Gallium Oxide Transistors for High Frequency Applications

提出的工作的目的是设计和演示高频β -氧化镓基晶体管。硅基电子产品无处不在，为许多应用提供了优异的性能，但仍存在某些关键技术领域，其他半导体材料，特别是宽带隙半导体，具有使其优于硅的特性。氧化镓就是这样一种半导体，其固有特性使其在高频通信等应用中具有潜在的优势。然而，为了利用这些特性获得更好的性能，需要开发新的设备工程（设计和制造）技术。拟议的研究项目侧重于基于这种材料的晶体管工程，这种材料可以实现比目前使用的典型无线通信技术更高范围的高频电子产品。随着网络智能设备和传感器在整个环境中的扩散，对高数据速率通信的需求正以前所未有的速度增长。因此，对具有高增益和高效率的高功率密度毫米波放大器的需求越来越大。本文提出的基于氧化镓的高功率毫米波晶体管的开发可以实现基于毫米波和太赫兹通信的新一代高数据速率系统。另外，还将开发以宽带隙半导体器件为中心的新课程，课程内容将在网上免费提供。该项目的主要目标是确定毫米波频率范围内氧化镓晶体管的频率和功率限制，并设计和演示具有最先进器件性能的晶体管。虽然氧化镓比氮化镓和碳化硅等其他宽带隙半导体具有更高的击穿场，但其载流子迁移率较低。此外，高场输运特性相对未知。该项目将引导对高尺度氧化镓晶体管的设计、生长、制造和表征的垂直整合研究。该项目将使人们更好地理解氧化镓器件工程的关键方面，包括外延设计，如δ掺杂晶体管和异质结构，以实现具有短栅极长度的缩放晶体管，理解这种缩放通道中的低场和高场电子传输，控制由表面和缓冲陷阱引起的色散。以及控制这些晶体管中的场分布所必需的场管理技术（如场板和钝化）。因此，拟议的项目将为基于氧化镓的新一代缩放晶体管奠定基础，科学发现不仅会影响高频晶体管，还会影响功率开关晶体管等其他技术。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The objective of the proposed work is to design and demonstrate high frequency Beta-Gallium Oxide based transistors. Silicon based electronics is ubiquitous and provides excellent performance for many applications, but there still remain certain critical technology areas where other semiconductor materials, particularly wide band gap semiconductors, have properties that make them superior to silicon. Gallium Oxide is one such semiconductor whose intrinsic properties make it potentially superior for applications such as high frequency communications. However, to harness these properties for better performance, new device engineering (design and fabrication) techniques need to be developed. The proposed research project focuses on engineering of transistors based on this material that could enable high frequency electronics in a range that is higher than the typical wireless communication technology used currently. With the proliferation of networked intelligent devices and sensors throughout our environment, the need for high data rate communication is increasing at an unprecedented rate. Therefore, there is a significant need for high power density mm-wave amplifiers with high gain and efficiency. The development of Gallium Oxide-based high power mm-wave transistors proposed here could enable a new generation of such high data rate systems based on mm-wave and THz communications. A new course focused on wide band gap semiconductor devices will also be developed, whose course content will be offered free online. The main goal of this project is to determine the frequency and power limits for Gallium Oxide transistors in the mm-wave frequency range, and to design and demonstrate transistors with state-of-art device performance. While Gallium Oxide has higher breakdown field than other wide band gap semiconductors such as Gallium Nitride and Silicon Carbide, it has lower carrier mobility. In addition, the high field transport characteristics are relatively unknown. This project will lead to a vertically integrated investigation of the design, growth, fabrication, and characterization of highly scaled Gallium Oxide transistors. The project will lead to a better understanding of critical aspects of device engineering for Gallium Oxide devices, including epitaxial designs such as delta-doped transistors and heterostructures to enable scaled transistors with short gate lengths, understanding of low and high field electron transport in such scaled channels, control of dispersion caused by surface as well as buffer traps, and field management techniques (such as field plates and passivation) necessary to control field distributions in these transistors. The proposed project will therefore lay the foundation for a new generation of scaled transistors based on Gallium Oxide, and the scientific findings will impact not just high frequency transistors, but also other technologies such as power switching transistors.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.