CAREER: Enhancing GaN-on-Si high electron mobility transistor technology for high frequency and high power applications

该项目由电气，通信和网络系统（ECCS）和刺激竞争研究的既定计划（EPSCoR）共同资助。GaN电子产品作为在广泛应用中取代硅电子产品的潜在候选者引起了人们的极大兴趣：从5G商用无线基础设施，电子战和通信应用到消费电子，数据中心，电动汽车，电网和可再生能源系统。GaN电子器件可以构建在各种衬底（即Si和SiC）上，其中GaN-on-Si由于其低成本和大规模能力而似乎是最有前途的技术。然而，GaN-on-Si技术仍然不成熟，并且不如GaN-on-SiC技术。必须深刻理解阻碍其执行的真实的原因。该提案旨在提供见解，以了解GaN-on-Si技术的基本问题，并开发提高其性能的能力。这项工作的成功实施有望彻底改变GaN-on-Si高电子迁移率晶体管技术，可应用于高频和大功率电子系统。什么融入研究活动是一个广泛的教育和推广工作，包括教育年轻人与新兴设备技术的小型化，集成和提高效率，开发新的课程和实习，与行业互动和传播K-12 Lithokit，这是有利于劳动力发展。所提出的工作解决了一些制造工艺面临的挑战，如果成功的话，将导致在高频和高功率应用的性能增强的硅基氮化镓技术。具体而言，通过一种新型的自对准T形栅极工艺，我们希望通过将其RF性能fT/fMAX提高到与GaN on SiC对应物相当的值，并将其功率性能提高到接近其理论极限，从而彻底改变GaN on Si技术。创新的自对准T形栅极工艺，其中T脚长度和主干高度可用于缩小栅极长度并最小化寄生电容以改善RF性能，并且T头可用作场板以提高器件功率性能。此外，所开发的栅极整流器和场板技术可以进一步扩展到用于功率应用的其他晶体管。所开发的材料和器件参数对所有其他GaN相关器件具有重要价值。该研究不仅将推动GaN-on-Si HEMT的基础科学和技术的发展，而且将为研究材料表面和界面性质与制造工艺之间的物理和化学关系提供范例，并为更深入地理解制造工艺与器件性能之间的关系提供帮助。从该计划开发的课程将教育年轻人与新兴设备技术的小型化，集成和提高效率，这是NSF的期望的社会影响之一。新的课程，实习，与行业的互动，以及K-12“Lithokit”将增加接触设备领域的观众，并有助于扩大劳动力。此外，通过产业合作计划，该技术的商业化潜力已经吸引了业界专业人士，这将极大地影响制造芯片的半导体公司。该奖项反映了NSF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。

This project is jointly funded by the Electrical, Communications and Cyber Systems (ECCS) and the Established Program to Stimulate Competitive Research (EPSCoR). GaN electronics attract much interest as the potential candidate to replace silicon electronics in a wide range of applications: spanning from 5G commercial wireless infrastructure, electronic warfare, and communications applications to consumer electronics, data centers, electric vehicles, electricity grid, and renewable energy systems. The GaN electronics can be built on various kinds of substrates (i.e. Si and SiC), in which the GaN-on-Si seems to be the most promising technology due to its low cost and large scale capability. However, the GaN-on-Si technology is still premature and is inferior to the GaN-on-SiC technology. A deep understanding of the real reasons for impeding its performance is indispensable. This proposal aims to provide insights to understand the fundamental problems of GaN-on-Si technology and develop the ability to enhance its performance. The successful implementation of this work is expected to revolutionize the GaN-on-Si high electron mobility transistor technology, which can be applied to high frequency and high power electronic systems. What integrated into the research activities is a broad scope of educational and outreach efforts including educating young people with emerging device technology for miniaturization, integration and improved efficiency, developing new courses and internships, interacting with industry and disseminating K-12 Lithokit, which are beneficial for workforce development. The proposed work addressing a number of fabrication process challenges facing GaN-on-Si technology that, if successful, will result in performance enhancement for both high frequency and high power applications. Specifically, through a novel self-aligned T-shaped gate process, we expect to revolutionize GaN-on-Si technology by enhancing its RF performance fT/fMAX to values comparable to its GaN-on-SiC counterpart and its power performance close to its theoretical limit. The innovative self-aligned T-shape gate process where the T-foot length and stem height can be used to downscale the gate length and minimize the parasitic capacitance for improved RF performance and the T-head can be adopted as the field plate to enhance device power performance. In addition, the developed gate dielectrics and field plate technology can be further extended to other transistors for power applications. The developed material and device parameters are of great value to all other GaN-related devices. The proposed research will not only advance the basic science and technology of the GaN-on-Si HEMTs, but also set an example for the investigation of the physical and chemical understanding of the relationship between material surface and interface properties and fabrication process and provide a deeper understanding of the relationship between the fabrication process and device performance. The courses developed from this program will educate young people with emerging device technology for miniaturization, integration and improved efficiency, which is one of the NSF’s desired societal impacts. The new courses, internships, interactions with industry, and K-12 “Lithokit” will increase the audience exposed to the device field, and help expand the workforce. In addition, through the collaborative industry programs, the potential to commercialize this technology has already attracted industry professionals, which will greatly impact semiconductor companies that fabricate chips.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.