Epitaxial Film Growth and Characterization of Stable and Metastable Gallium-Aluminum-Oxide Polymorphs

非技术描述：半导体在日常生活中无处不在，是工业制造、通信、运输、能源转换和传输以及许多其他应用中的关键部件。 美国《芯片与科学法案》提供了500多亿美元用于增加国内半导体研究和制造，进一步凸显了半导体研究对美国国家安全和经济的至关重要性。该研究项目创造了生产新型半导体合金系统的科学知识，并为开发和制造可在极端环境下工作的未来半导体器件提供了平台。 半导体器件在更高温度和更高功率下工作的能力转化为大量的能源节约和更高效、更强大的可再生能源技术，如远程电动汽车。作为未来劳动力的一部分，研究生和本科生将获得半导体行业所需的新加工方法和先进表征工具方面的广泛技能。外展活动还教育初中/高中学生关于半导体和相关材料的知识，以激励他们考虑STEM职业。从这项研究中产生的材料和生长配方推进了半导体&研发活动：外部研究小组可以通过在卡内基梅隆大学的洁净室用户设施中的设备上进行培训来生产或获得半导体薄膜，向洁净室工作人员索取收费服务薄膜，或者通过与主要研究者建立的研究合作。技术描述：本计画系研究镓铝氧化物磊晶薄膜之不同相或多晶型物之成长与特性，其对于可在极端条件下操作的高效电力电子器件具有巨大的潜力。将氧化镓与Al合金化以形成具有独特性质和取决于Al含量的可调超宽带隙的AGO的不同多晶型物的能力呈现了具有形成用于已建立的和新颖的半导体器件的平台的潜力的巨大材料系统。因此，该项目的最终目标是实现对AGO半导体外延膜的相含量和微结构的前所未有的控制。然而，对如何控制该材料系统中一个相相对于另一个相的生长的理解非常有限。使用化学气相沉积生产的薄膜，这项研究有助于了解如何热力学和动力学变量可以用来控制作为Al含量的函数的AGO的稳定和亚稳的多晶型物的生长。以前的实验和理论研究作为参考点，并通知实验方法。 采用先进的材料表征工具来识别膜中的微/纳米结构、相含量和组成，并揭示膜内和膜/基底界面处的相互扩散和相变等现象，这些现象决定了所得膜生长的性质。 对具有最佳结构特性的薄膜进行电测量，可以发现与基于这些材料的未来电子设备相关的特性。该奖项反映了NSF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。

Nontechnical description:Ubiquitous in every-day life, semiconductors are critical components in industrial manufacturing, communications, transportation, energy conversion and transmission, and many other applications. The U.S. CHIPS and Science Act, which provides more than $50 billion to increase domestic research and manufacturing of semiconductors, further highlights the critical importance of semiconductor research to U.S. national security and the economy. This research project creates scientific knowledge to produce a novel semiconductor alloy system and forms a platform for the development and manufacturing of future semiconductor devices that can operate in extreme environments. The capability for semiconductor devices to operate at higher temperatures and higher powers translates to substantial energy savings and more efficient and robust renewable energy technologies, such as long-range electric vehicles. As part of the future workforce, graduate and undergraduate students gain a broad set of skills in new processing methods and advanced characterization tools that are needed in the semiconductor industry. Outreach activities also educate middle/high-school students about semiconductors and related materials to inspire them to consider careers in STEM. The materials and growth recipes resulting from this research advance semiconductor R&D activities: external research groups can produce or acquire semiconductor films through training on the equipment located in Carnegie Mellon University’s clean room user facility, requesting fee-for-service films from clean room staff, or through an established research collaboration with the principal investigator.Technical description:This project is a research investigation on the growth and characterization of different phases, or polymorphs, of gallium-aluminum-oxide (AGO) epitaxial films, which have enormous potential for high-efficiency power-electronic devices that can operate in extreme conditions. The ability to alloy gallium oxide with Al to form different polymorphs of AGO with unique properties and tunable, ultra-wide bandgaps that depend on Al content presents a vast materials system with potential to form a platform for both established and novel semiconductor devices. As such, an ultimate goal of this project is to achieve unprecedented control over the phase content and microstructure of AGO semiconductor epitaxial films. However, the understanding of how to control the growth of one phase versus another in this material system is very limited. Using chemical vapor deposition to produce the films, this research contributes to the understanding of how thermodynamic and kinetic variables can be used to control the growth of stable and metastable polymorphs of AGO as a function of Al content. Prior experimental and theoretical studies serve as points of reference and inform the experimental approach. Advanced materials characterization tools are employed to identify the micro-/ nano-structure, phase content and composition in the films and reveal such phenomena as interdiffusion and phase transitions within the film and at the film/substrate interface, which determine the nature of the resulting film growth. Electrical measurements of films showing optimum structural characteristics uncover properties that are relevant for future electronic devices based on these materials.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.