EAGER: Flexible III-N High-Electron-Mobility Transistors with Controlled External Bending Strains for Wide-Bandgap Semiconductor Devices

2014年诺贝尔物理学奖认可，第三组氮化物(III-N)半导体作为节能环保的光源，为人类带来了重大利益。它们也是节能电力转换和开关、无线通信、电子战和光存储系统的重要材料。该项目建议研究利用设备结构的机械弯曲来扩展功能和进一步增强已经高性能和高效率的设备的性能。该项目预计将产生新概念的器件和相关的新器件物理，以促进器件技术知识的进步。此外，这项研究的结果将提供一个潜在的颠覆性半导体平台，可以集成到其他具有多功能和应用多功能性的半导体设备中，以实现节能和收获。这一新概念是在理论研究的基础上提出的，还有待于工作装置的演示，这是拟议项目的主要目标之一。这将对社会和经济产生重大影响，因为基于半导体的电子、光电子和能源系统是现代技术的支柱，随着电动汽车和智能电网系统的采用，未来将更加关键。例如，30%的电能通过电力电子转换器，22%的总发电量消耗在照明上，这意味着在节能和减少温室气体排放方面有望产生显著的效益。与研究计划相结合的教育和推广计划将有助于传播关于绿色能源系统、可持续技术的半导体器件及其社会和环境影响的知识。基于III-N异质结构的柔性器件可以配备新的功能，甚至通过利用其自发极化和压电极化的独特特性，比基于晶片的非柔性器件具有更高的性能特性。因此，通过主动控制不同外部应变的偏振，它们为新概念器件、多功能机电光子(MEP)器件提供了机会，而不仅仅是机械柔性器件。该项目的目标是证明有源偏振工程的概念在柔性III-N结构中的应用，并为MEP器件在电子、光子和能量收集方面的应用奠定基础。利用柔性异质结中的电学、光学性质和机械力之间的相互作用，将开发基于III-N半导体的各种多功能和/或更高性能的MEP器件。通过建模和实验研究，研究弯曲应变可控的柔性高电子迁移率晶体管基本特性的变化，以验证所提出的有源极化工程概念。技术方法和任务包括(1)不同曲率半径的器件模拟，(2)开发可弯曲器件的高保真制造工艺，以及(3)开发用于MEP器件操作的物理模型。该项目是生产概念验证的主动极化工程电子器件和相关的新器件物理，以展示新技术平台的潜力。MEP器件有可能从根本上改变对III-N半导体器件的理解和应用，从而产生新型器件和系统。新的设备物理和建模结果，包括静态和动态外部应变的影响，将为各种应用提供此类设备的理论背景。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。

Group III-Nitride (III-N) semiconductors have brought significant benefits to mankind as energy-efficient and environment-friendly light sources, as recognized by the Nobel Prize in Physics 2014. They are also important materials for energy-efficient electric power conversion and switching, wireless communication, electronic warfare, and optical storage systems. This project proposes to study the expanded functionality and further enhanced performance of the already high-performance and high-efficiency devices using mechanical bendability of the device structure. This project is expected to produce new-concept devices and related new device physics for the advancement of knowledge in the device technology. Furthermore, the outcome of this research will provide a potentially disruptive semiconductor platform that can be integrated in other semiconductor devices with multi-functionality and application versatility for energy saving and harvesting. The new concept has been developed based on theoretical studies and has yet to be proven by the demonstration of working devices, which is one of major objectives of the proposed project. The societal and economic impacts will be significant because electronics, photonics, and energy systems based on semiconductors are the backbone of modern technology and will be even more critical in the future with the adoption of electric vehicles and smart-grid systems. As an example, 30% of electrical energy passes through power electronics converters and 22% of total generated electricity is consumed in lighting, which means that significant benefits are expected in energy saving and reduction of greenhouse-gas emission. Education and outreach programs integrated with the research program will contribute to the dissemination of knowledge on green energy systems, semiconductor devices for sustainable technology, and their societal and environmental impacts.Flexible devices based on III-N heterostructures can be equipped with new functionalities and even further improved performance characteristics compared to wafer-based non-flexible devices by exploiting their unique properties of spontaneous and piezoelectric polarizations. Therefore, they open an opportunity to new-concept devices, multi-functional mechano-electro-photonic (MEP) devices, beyond just mechanically flexible devices, by the active control of the polarizations with variable external strains. The goals of the project are to prove the concept of the active polarization engineering applied in flexible III-N structures and to lay the foundation for the MEP devices in electronic, photonic, and energy-harvesting applications. Various multi-functional and/or higher-performance MEP devices based on III-N semiconductors will be developed by utilizing the interactions between electronic and optical properties and mechanical forces in the flexible heterostructures. The changes in fundamental characteristics of flexible high-electron-mobility transistors with controlled bending strains will be investigated via both modeling and experimental studies to prove the proposed concept of active polarization engineering. Technical methods and tasks include (1) device simulation with various curvature radii, (2) the development of high-fidelity fabrication process for bendable devices, and (3) the development of a physical model for the operation of MEP devices. This project is to produce proof-of-concept actively polarization-engineered electronic devices and related new device physics to demonstrate the potential of a new technology platform. The MEP devices offer the potential to radically change the understanding and applications of III-N semiconductor devices, leading to the creation of new-type devices and systems. New device physics and modeling results including the effect of static and dynamic external strains will provide a theoretical background of such devices for various applicationsThis 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.