US-Ireland Collaborative Research on Nanostructured Gallium Nitride (GaN) Power Semiconductor Devices

随着能源消费需求的扩大，世界面临着节约能源和减少碳排放的严峻挑战。随着可再生能源的使用、交通电气化、高效电加热和制冷的扩展、信息交通的扩展、工业电机使用的增加以及新的智能电网的发展，我们的世界进一步电气化，预计对电力的需求将显著增加。先进的宽带隙（WBG）半导体电力电子将在电力生命周期的各个阶段发挥关键作用，包括发电、配电和消费，并有可能将电力效率提高10-25%。氮化镓（GaN）功率器件为电动汽车、电机驱动、并网可再生逆变器、超紧凑型电源和许多其他能量转换系统提供了高性能解决方案。然而，当今制造工艺中的材料缺陷阻碍了这种潜力的充分实现。美国、爱尔兰共和国和北爱尔兰研究人员之间的这一国际合作项目将解决GaN材料缺陷、可靠性和成本方面的基本挑战，并可能对WBG电力电子行业产生重大影响。该项目的目标是探索基于GaN纳米线的高压垂直器件架构，并推进对材料生长和缺陷机制、电击穿和输运特性的基本理解，为电力电子应用建立可行的纳米技术构建模块。该方法是在硅衬底上采用选择性区域金属有机气相外延（MOVPE）生长的纳米gan材料上建模、制造和表征高压肖特基势垒二极管、合并PiN肖特基二极管和栅极全方位场效应晶体管。美国-爱尔兰合作研究项目结合了爱尔兰Tyndall国家研究所的MOVPE增长和纳米制造能力，北爱尔兰贝尔法斯特女王大学的材料分析能力以及伊利诺伊理工学院的设备建模、设计和测试专业知识。本研究的智力价值在于为减少或消除位错和提高宽WBG功率半导体的可靠性开辟了一个新的方向，从而导致在硅平台上的新型高压GaN器件架构。这与基于异质外延薄膜的主流横向GaN器件结构明显不同。该项目将解决与纳米和微尺度器件设计和建模、纳米异质外延材料生长和表征以及器件制造相关的基础和应用研究。它将促进对一维半导体外延生长动力学的基本理解，以及facet表面态对载流子输运和器件击穿特性的影响。

The world is facing serious challenges in conserving energy resources and reducing carbon emissions as demand for energy consumption expands. The demand for electricity is expected to increase significantly with further electrification of our world driven by renewable energy usage, electrification of transportation, expansion of efficient electrical heating and cooling, expansion of information traffic, increased industrial motor usage, and new smart grid development. Advanced wide bandgap (WBG) semiconductor power electronics will play a critical role in all phases of the electricity life cycle including generation, distribution and consumption, and have the potential to improve electricity efficiency by 10-25%. Gallium Nitride (GaN) power devices offer a high performance solution in electric vehicles, motor drives, grid-tied renewable inverters, ultra-compact power supplies, and many other energy conversion systems. However, material defects in today's fabrication processes prevent full realization of this potential. This international collaboration project between the US, Republic of Ireland and Northern Ireland investigators will address the fundamental challenges on GaN material defects, reliability, and cost, and potentially has a large impact to the WBG power electronics industry. The objective of the project is to explore high voltage vertical device architectures based on GaN nanowires, and advance the fundamental understanding of materials growth and defect mechanisms, electrical breakdown and transport properties to establish a viable nanotechnology building block for power electronics applications. The approach is to model, fabricate, and characterize high voltage Schottky barrier diodes, merged PiN Schottky diodes, and gate-all-around field effect transistors on nano-GaN materials grown with selective area metalorganic vapor phase epitaxy (MOVPE) on silicon substrates. The US-Ireland collaborative research project combines the MOVPE growth and nanofabrication capabilities at Tyndall National Institute in Ireland, the material analysis capabilities at Queen's University Belfast in Northern Ireland with the device modeling, design, and testing expertise at Illinois Institute of Technology. The intellectual merit of this research is to open up a new direction in reducing or eliminating dislocations and improving reliability of wide WBG power semiconductors, leading to novel high voltage GaN device architectures on a silicon platform. This is distinctly different from the mainstream lateral GaN device architectures based on heteroexpitaxial thin-films. The project will address fundamental and applied research related to nano- and micro-scale device design and modeling, nanoheteroexpitaxial materials growth and characterization, and device fabrication. It will advance the basic understanding of one-dimensional semiconductor epitaxial growth kinetics and the effects of facet surface states on carrier transport and device breakdown properties.