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

随着能源消费需求的扩大，世界在节约能源和减少碳排放方面面临严峻挑战。随着可再生能源的使用、交通的电气化、高效电力供暖和制冷的扩大、信息交通的扩大、工业电机使用的增加以及新型智能电网的发展，对电力的需求预计将显著增加。先进的宽带隙(WBG)半导体电力电子技术将在电力生命周期的所有阶段发挥关键作用，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)功率器件在电动汽车、电机驱动、并网可再生逆变器、超紧凑型电源和许多其他能源转换系统中提供高性能解决方案。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调查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根本挑战，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，促进对材料生长和缺陷机制、电击穿和输运特性的基本了解，为电力电子应用建立可行的纳米技术基础。该方法是在硅衬底上用选择性区域金属有机气相外延(MOVPE)生长的纳米GaN材料上对高压肖特基势垒二极管、合并的PIN肖特基二极管和栅全场效应晶体管进行建模、制造和表征。美国-爱尔兰合作研究项目将爱尔兰廷德尔国家研究所的MOVPE生长和纳米制造能力、北爱尔兰贝尔法斯特女王大学的材料分析能力与伊利诺伊理工学院的器件建模、设计和测试专业知识结合在一起。这项研究的学术价值在于为减少或消除位错，提高宽幅带功率半导体的可靠性开辟了新的方向，导致了在硅平台上新型高压GaN器件结构的出现。这与主流的基于异质外延薄膜的横向GaN器件结构有很大的不同。该项目将致力于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以及小平面表面态对载流子输运和器件击穿特性的影响的基本理解。

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.