ASCENT: Enabling efficient high power grid applications by high voltage rating ultrawidebandgap transistors

该项目旨在了解新兴的超宽带隙半导体氧化镓的科学和开发工程，用于下一代高压，大电流电力电子产品。电力电子在一些创新技术中起着至关重要的作用，包括可再生能源与电网、电动汽车、飞机和船舶的整合。多学科团队解决了几个挑战，从低缺陷密度材料的合成到高功率转换器中器件原型的应用和基准测试。在高功率应用中，一个重要的挑战是在器件运行过程中管理散热的能力。该项目通过将氧化镓与高导热材料相结合来解决这一挑战，这种材料可以有效地散热。此外，将为高电压、高功率和低损耗操作开发创新的器件设计和电路拓扑。该计划的成功将使功率器件和电路技术超越最先进的技术。这项新技术将促进电力电子市场的创新。该项目的基础研究方面将增加对超宽带隙半导体电子特性的理解，这些半导体在电力电子以外的应用。对参与该项目的不同学生的教育和培训将提高他们在半导体制造方面的技术技能。国内半导体制造目前是美国经济领导地位和国家安全的国家优先事项。教育推广活动将与研究任务结合起来。推广工作的目标是培养初高中学生对科学和工程领域的兴趣，特别是针对来自代表性不足的少数民族（URM）的学生。β -氧化镓（Ga2O3）具有较低的背景掺杂密度、良好的掺杂控制和达到理论预测值的电子迁移率。大的预测和实验证明的电场强度和良好的电子迁移率使其成为高电压（10 kV）额定功率器件的有吸引力的半导体。这种高额定电压可以在薄漂移层中实现，这种漂移层可以通过金属有机化学气相沉积（MOCVD）以低缺陷密度和高均匀性生长。该项目利用MOCVD生长的原位掺Mg电流阻挡层的实验演示。该团队还展示了将氧化镓集成到高导热基板上。本项目的科学目标是：(1)开发和优化高电压、高功率工作用低可控掺杂的原位掺Mg阻流层和厚Ga2O3漂移层；（ii）设计、制造和测量具有高击穿阻断能力的高功率mosfet；（iii）将功率器件异质集成到高导热基板上进行热管理；（iv）研究开关损耗和并联技术，并对使用开发的功率器件的实际电路进行基准测试。如果成功，所提出的创新器件将使额定电压超过10千伏的高效大功率开关成为可能，从而大大降低成本并提高大功率电路的效率。这些技术可以加速可再生能源与电网的整合，并导致真正的智能电网运行。综合教育计划旨在透过直接参与拟议的研究活动，教育和激励年轻学生，特别是女学生，以及来自URM小组的学生，从事STEM学习和职业。为本科生和研究生提供的研究机会将有助于为国内制造业培养未来半导体劳动力的技能，并保持美国的经济竞争力。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。

This project aims to both understand the science and develop engineering of an emerging ultra-widebandgap semiconductor, gallium oxide, for the next generation high voltage, high current power electronics. Power electronics plays an essential role in several innovative technologies including integration of renewables to grid, electric cars, planes, and ships to name a few. The multidisciplinary team addresses several challenges spanning from the synthesis of low defect density materials to applications and benchmarking of device prototypes in high power converters. An important challenge in high power applications is the ability to manage heat dissipation during the device operation. This project addresses this challenge by integrating gallium oxide with a high thermal conductivity material which can efficiently dissipate heat. Additionally, innovative device designs and circuit topologies will be developed for high voltage, high power and low loss operation. Success in the program would enable power device and circuit technologies beyond the state-of-the-art technologies. The new technology would foster innovation in power electronics market. The fundamental study aspects of the project would increase the understanding of the electronic properties of ultra-widebandgap semiconductors which have applications beyond power electronics. The education and training of the diverse students working on the project would enhance their technical skills in semiconductor manufacturing. Domestic semiconductor manufacturing is currently a national priority for US economic leadership and national security. Educational outreach activities will be integrated with research tasks. The goal of the outreach efforts is to inculcate interest of middle and high school students to science and engineering fields, specifically targeting students from underrepresented minorities (URM). Beta-gallium oxide (Ga2O3) has achieved robust maturity with low background doping densities, excellent doping control and electron mobilities reaching theoretically predicted values. The large predicted and experimentally demonstrated electric field strengths and good electron mobility makes it an attractive semiconductor for high voltage ( 10 kV) rating power devices. Such high voltage ratings can be achieved in thin drift layers that can be grown with low defect densities and high uniformity by metal organic chemical vapor deposition (MOCVD). The project leverages the experimental demonstration of in-situ Mg doped current blocking layers grown by MOCVD. The team has also demonstrated integration of gallium oxide onto high thermal conductivity substrates. The scientific objectives of this project are (i) developing and optimizing in-situ Mg doped current blocking and thick Ga2O3 drift layers with low controllable doping for high voltage and high power operation; (ii) design, fabrication, and measurement of high power MOSFETs with high breakdown blocking capability; (iii) heterogeneous integration of the power devices onto high thermal conductivity substrates for thermal management and (iv) investigation of switching losses and paralleling techniques, as well as benchmarking of practical circuits using the developed power devices. If successful, the proposed innovative device will enable efficient high-power switches with beyond 10 kV voltage ratings thus drastically reducing the cost and increasing the efficiency of high-power circuits. These technologies can accelerate the integration of renewables to the grid and lead to truly smart grid operation. The integrated education plan aims to educate and motivate young students, especially female students, and those from the URM groups, to pursue STEM studies and careers by direct participation in the proposed research activities. The research opportunity given to undergraduate and graduate students will help build the skills of the future semiconductor workforce for domestic manufacturing and maintain the economic competitiveness of the US.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.