NSF/ENG/ECCS-BSF: Semiconductor Polytype Heterostructures: A Pathway to Superior Power Electronics

NSF/ENG/ECCS-BSF：半导体多型异质结构：通往卓越电力电子器件的途径

• 批准号: 2240388
• 负责人: Rachel Goldman
• 金额: $ 45万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-15 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2240388&HistoricalAwards=false
• 关键词: NSF; ENG; ECCS; BSF; Semiconductor

Non-technical Description: This project aims to develop a new building block for electronics, semiconductor polytype heterostructures, which consist of adjacent layers of lattice-matched materials differing only in their atomic stacking sequences. Semiconductor polytype heterostructures are expected to result in the formation of a polarization-doped two-dimensional electron gas, with both high carrier concentration and high carrier mobility, resulting in ultra-high conductivity; thus, they are expected to offer a timely solution to a near-decade plateau in transistor speed. The project provides training to graduate, undergraduate, and high school students, engaging them in a collaboration between the University of Michigan and Ben-Gurion University. The collaboration integrates the expertise of the U.S. investigators (molecular-beam epitaxy and crystallographic characterization of semiconductor polytype films and heterostructures) with that of the Israeli investigators (spectroscopic characterization of polytype heterostructures and fabrication/characterization of high-electron mobility transistors). The new knowledge gained will be broadly disseminated through publications and presentations, and graduate and undergraduate curriculum development. Outreach activities emphasize the mentoring of women and underrepresented minorities.Technical Description: The project seeks new understanding ZB vs. WZ polytype selection and the electronic states/transport properties of ZB/WZ polytype heterostructures, thereby informing strategies for fabrication of polytype heterostructures. The interplay between surface reconstruction, polytype selection, and local electronic states will be monitored in real-time during epitaxy using in-situ reflection high-energy electron diffraction (RHEED), multi-beam optical stress sensing, and scanning-tunneling microscopy. In addition to examining growth kinetics, the influence of electrostatic phenomena, including thermal and electron-induced charging, on WZ vs. ZB polytype selection in both ZB-preferring (GaAs) and WZ-preferring (GaN) materials will be explored. A machine-learning approach using convolutional neural networks will be used to quantify and classify RHEED patterns, thereby accelerating the process of identifying appropriate growth kinetics and induced surface charging to select WZ vs. ZB polytypes. Following epitaxy, the interface structure and polarity will be examined using high-resolution and scanning transmission electron microscopy, selected-area and convergent-beam electron diffraction, and x-ray diffraction. The electronic states will be examined using scanning tunneling spectroscopy and optical spectroscopic tools based upon the Franz-Keldysh effect. Upon identification of the key growth kinetics and/or electrostatic phenomena to tailor polytype selection, ZB/WZ polytype hetero-structures for HEMTs will be fabricated. Expected outcomes of this work include the identification of strategies for polytype selection during epitaxy of thin films that prefer the ZB or WZ polytype, as well as the design and fabrication of ZB/WZ polytype HEMT structures that will facilitate the discovery of new strategies for transistors, with the potential for integration of logic and memory beyond Moore's Law.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.

非技术描述：该项目旨在为电子设备，半导体多型异质结构开发一个新的构建块，该结构由仅在其原子堆叠序列不同的晶格匹配材料的相邻层组成。半导体多型异质结构预计会导致形成偏振掺杂的二维电子气体，具有高载体浓度和高载体迁移率，导致超高电导率。因此，预计他们将及时解决晶体管速度近十年的高原。该项目为研究生，本科和高中生提供了培训，使他们参与了密歇根大学和本·古里安大学之间的合作。该协作将美国调查人员的专业知识（分子梁的外观和晶体学表征）与以色列研究者的专业知识与以色列研究者的专业知识（多型异质结构的光谱表征）和高电动迁移式晶体管的表征）。 获得的新知识将通过出版物和演讲以及研究生和本科课程开发大致传播。推广活动强调了妇女的指导和代表性不足的少数群体。技术描述：该项目寻求新的了解ZB与WZ PolyType选择以及ZB/WZ PolyType异质结构的电子状态/运输特性，从而为制造Polytype杂质结构的制造策略提供了信息。使用原位反射高能电子衍射（RHEED），多光束光学应力感应和扫描 - 隧道显微镜，将在外交期间实时监测表面重建，多型选择和局部电子状态之间的相互作用。除了检查生长动力学外，还将探索静电现象（包括热和电子诱导的充电）对WZ与ZB多型ZB多型选择的影响。使用卷积神经网络的机器学习方法将用于量化和分类Rheed模式，从而加速识别适当的生长动力学和诱导表面充电以选择WZ与ZB多型的过程。在外观上，将使用高分辨率和扫描透射电子显微镜，选定区域和收敛梁电子衍射以及X射线衍射来检查界面结构和极性。将使用基于Franz-Keldysh效应的扫描隧道光谱和光谱工具来检查电子状态。在鉴定关键生长动力学和/或静电现象以量身定制多型选择时，将制造ZB/WZ多型异型结构。这项工作的预期结果包括鉴定更喜欢ZB或WZ多型的薄膜的多型型策略，以及ZB/WZ Polytype Hemt结构的设计和制造，这些结构将促进晶体的新策略，并涉及logic和Moore Laws of Moore law的潜力，并涉及Moore ward的潜力。值得通过基金会的智力优点和更广泛的影响审查标准来通过评估来支持。