ASCENT: Reducing greenhouse emissions with ultra-efficient High-Voltage Monolithic Bidirectional Transistors

温室气体排放是全球气候动态变化的主要因素。根据美国环境保护局的数据，总温室气体排放源的50%分别与发电(25%)和交通(27%)有关。考虑到到2030年，预计80%的总发电量将通过电力电子设备流动，这就迫切需要有效地利用可用电力。随着现代电网和交通运输电气化程度的提高，超高效率的双向潮流正迅速成为一种新的需求。电网(例如，太阳能从消费者到电网以及从电网到消费者，消费者作为存储和分配元件)、电动汽车(例如，从汽车到电网、电网到汽车、汽车到另一辆汽车、汽车作为电能的来源和消费者)、工业电机驱动器、固态变压器、数据中心电源、电梯驱动器、直流微电网、储能等。所有这些应用都推动电力电子产品在所有形式的电力消费和生产中迅速扩张；因此，它们的建设是可持续的、紧凑的，并且高效运行是至关重要的。然而，现有的电路解决方案以及支持双向功率流的半导体器件会导致占用空间大、效率降低和容错能力低。NSF的这项提案旨在采取材料、器件和电路共同设计的方法，以同时应对半导体器件和电路的挑战。我们建议利用矩阵转换器(MC)和电流源逆变器(CSI)等电路体系结构和适当设计的半导体晶体管(即双向晶体管)来提供内聚解决方案。双向晶体管具有在两个方向上阻断电压和传导电流的能力。通过我们的多抽象层次的协作研究，将开发新的材料和双向器件的合成和制造步骤，将获得对双向晶体管操作的器件和电路级别的了解，并将展示和基准这些器件在MC和CSI逆变器拓扑中的性能。这项研究工作将与教育和劳动力发展活动以及扩大K-12、大学预科和大学生参与的努力相辅相成。这项提议的主要目标是利用宽带隙材料(WBG)和超宽带隙材料(UWBG)开发超高效、高压单片双向晶体管(MBDT)，用于高效的双向功率流使能电路。本项目将围绕这些研究目标展开。1)首次展示了基于UWBG的单片双向晶体管(MBDT)。2)通过材料-器件协同设计，同时提高GaN单片双向晶体管的性能和可制造性。3)开发一种独特的高导电性多通道UWBG(AlGaN)材料，与现有解决方案相比，该材料可导致10倍的传导损耗。4)全面了解单片双向晶体管中的物理现象--电子陷阱、磁滞、击穿机制、电流崩溃、热极限、稳健性和可靠性。5)与现有解决方案相比，采用单片双向晶体管演示了转换器拓扑结构和基准测试效率。我们的劳动力教育、培训和发展努力将包括通过促进实习机会、午餐研讨会网络和课程重新设计来促进学生与行业的合作。此外，我们将与工业和当地麦迪逊地区的技术学院合作，设计课程，以满足不断增长的技术人员和操作员的需求。我们将通过在未充分代表和贫困的大学预科学生中开展外展活动来扩大参与度，并通过在威斯康星州科学节和工程博览会上的一项新活动来提高K-12级别对智能能源选择及其对环境影响的认识。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Greenhouse gas emissions are the primary contributors for the change in global climate dynamics. According to the U.S. Environment and Protection Agency, 50% of the total greenhouse gas emissions sources are tied to electricity generation (25%) and transportation (27%), respectively. This places an urgent need for efficient utilization of available electric power, considering 80% of the total generated electric power is expected to flow through power electronics by 2030. With the rising electrification of the modern grid and transportation, ultra-efficient bidirectional power flow is fast becoming an emerging requirement. Bidirectional power flow can be witnessed in a grid (for example, solar energy from consumer to grid and from grid to consumer, consumer as storage and distribution element), electric car (for example, from car to grid and grid to car, car to another car, car as a source and consumer of electric power), industrial motor drives, solid-state transformers, data center power supplies, elevator drives, DC microgrids, energy storage, etc. All these applications drive the rapid expansion of power electronics across all forms of electrical power consumption and production; thus, it is critical that their construction is sustainable, compact, and they operate efficiently. However, incumbent circuit solutions as well as semiconductor devices that support bidirectional power flow result in large footprint, reduced efficiency, and low fault tolerance. This NSF proposal aims to take a materials, devices, and circuit co-design approach to tackle both semiconductor device and circuit challenges simultaneously. We propose to utilize circuit architectures such as matrix converters (MCs) and current source inverters (CSIs) with suitably designed semiconductor transistors, i.e., bidirectional transistors, to present a cohesive solution. Bidirectional transistors have the capability to block voltage and conduct current in both directions. Through our multi-abstraction level collaborative research, novel material and bidirectional device synthesis and fabrication steps will be developed, device and circuit level understanding of bidirectional transistor operation will be gained and the performance of these devices in MC and CSI inverter topologies will be demonstrated and benchmarked. This research effort will be complemented with efforts for education and workforce development activities as well as broadening participation amongst K-12, pre-college, and college students.The key objective of this proposal is to leverage wide bandgap materials (WBG) and ultra-wide-bandgap (UWBG) materials to develop ultra-efficient, high-voltage monolithic bidirectional transistor (MBDT) to be utilized in efficient bidirectional power flow enabling circuits. This project will focus on these research goals. 1) Demonstration of the first UWBG based monolithic bidirectional transistors (MBDT). 2) Enhancing the performance of GaN Monolithic Bidirectional Transistor and manufacturability simultaneously by material-device co-design. 3) Development of a unique high-conductivity multi-channel UWBG (AlGaN) material development which can lead to 10x conduction losses compared to incumbent solutions. 4) Develop comprehensive understanding of physical phenomenon electron-trapping, hysteresis, breakdown mechanisms, current collapse, thermal limits, robustness, and reliability in monolithic bidirectional transistors. 5) Demonstration of converter topologies and benchmarking efficiency with the introduction of monolithic bidirectional transistors compared to incumbent solutions. Our workforce education, training, and development efforts will include fostering student-industry collaboration by facilitating internship opportunities, lunch seminar networking, and curriculum redesign. Additionally, we will work with industry and local Madison area technical colleges to design courses to meet rising technician and operator needs. We will broaden participation by performing outreach activities with under-represented and underprivileged pre-college students and increase awareness at the K-12 level on smart energy choice and their impact on the environment with a new activity at the Wisconsin Science Festival and Engineering Expo.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.