EFRI 2DARE: Thermal Transport in 2D Materials for Next Generation Nanoelectronics- From Fundamentals to Devices

EFRI 2DARE：下一代纳米电子学二维材料中的热传输 - 从基础知识到设备

• 批准号: 1542864
• 负责人: Amin Salehi-Khojin
• 金额: $ 200万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1542864&HistoricalAwards=false
• 关键词: EFRI; 2DARE; Thermal; Transport; 2D

Computers and other current microelectronic devices based on silicon technology contain central processing units that produce excess heat while performing calculations and other tasks. This thermal energy migrates to the surface of the silicon chip and is dissipated by fans or other means (e.g., fluid cooling). However, as engineers seek to increase the transistor count per chip for greater computer power, silicon technology reaches its limit, and a different base material with a different hardware architecture will be needed. Recently, sheets of material have been developed which are only one atomic layer thick and which may function as semiconductors (transition metal dichalcogenides), conductors (graphene), or insulators (boron nitride)?the main elements of any electronic device. Transistors have already been developed by stacking these different atomic layers. However, the power density and tendency for such devices to overheat increase dramatically at such a small scale. Therefore, no practical devices from these materials will be possible until the physics of heat transfer at this scale is better understood and the heat dissipation problem is solved. This proposal seeks to comprehensively study the thermal transport dynamics of stacks of atomic layers of semiconductors, conductors, and insulators representative of future nano-electronic devices. The multidisciplinary team consists of a mechanical engineer, an electrical engineer, a chemist, and two physicists from three different universities. Each university has special programs for involving undergraduate and underrepresented minority students in research. The investigators will engage PhD students and undergraduate minority students as well as high school students in this combined experimental and theoretical study aimed at benefiting society through the development of a comprehensive picture of the dominant contributions and limitations of heat transport in future 2D devices.The primary goal of this proposal is to provide the community with a deeper understanding of the limits set by the kinetics of dissipation and heat removal through various junctions and interfaces in two-dimensional heterogeneous materials. The team aims to establish a multiscale thermal transport study through a closely coupled combination of material synthesis and device-level experiments, atomic-level characterization, thermal transport and phonon spectroscopy, theoretical modelling, and computational studies. Transformative synthesis/fabrication methods, such as chemical vapor deposition and atomic layer deposition, will be used to produce hetero-structures of interest as fundamental components of any electronic devices. The in-plane and out-of-plane thermal conductivity of the synthesized structures will be measured using a custom-designed electrical thermometry platform. The length scale dependence of thermal conductivity and the mean free path (MFP) distribution of heat-carrying phonons will also be measured by heterodyne transient grating technique. In-situ scanning thermal microscopy characterization will be performed to study self-heating of selected semiconducting 2D materials at their contact metal electrodes under high-power operational conditions. Atomic-resolution scanning transmission electron microscopy will be used to characterize 2D material interfaces and surfaces. Characterization results will guide molecular dynamics simulations to predict the atomic structures of interfaces and grain boundaries and to quantify the effects of small-scale structural variations on thermal transport properties of the materials. Thermal transport, including the full spectrum of phonon MFPs, will be calculated using the phonon Boltzmann transport equations including intrinsic phonon scattering as well as scattering at interfaces. The simulation results and Boltzmann transport calculations of phonon MFP distributions will be benchmarked against the transient grating measurements and device level data to develop a predictive model for thermal dissipation in 2D heterogeneous materials. The proposed research has a transformative potential and is of high relevance across many research fields. The broader impacts of this work will be significant in enabling the design of new classes of 2D heterogeneous materials for future electronics/optoelectronics from a thermal management perspective.

计算机和其他当前基于硅技术的微电子设备包含中央处理器，这些处理器在执行计算和其他任务时会产生多余的热量。这种热能迁移到硅芯片的表面，并通过风扇或其他方式(例如，流体冷却)来耗散。然而，随着工程师寻求增加每个芯片的晶体管数量以获得更大的计算机能力，硅技术达到了极限，将需要具有不同硬件架构的不同基材。最近，已经开发出只有一个原子层厚的材料片，这些材料可以用作半导体(过渡金属二卤化物)、导体(石墨烯)或绝缘体(氮化硼)--任何电子器件的主要元素。通过堆叠这些不同的原子层，晶体管已经被开发出来。然而，在如此小的规模下，这类设备的功率密度和过热倾向急剧增加。因此，在更好地理解这种尺度下的热传递物理并解决散热问题之前，这些材料的实际装置是不可能的。这项建议旨在全面研究代表未来纳米电子器件的半导体、导体和绝缘体原子层堆叠的热传输动力学。这个多学科团队由一名机械工程师、一名电气工程师、一名化学家和来自三所不同大学的两名物理学家组成。每所大学都有专门的项目，让本科生和少数族裔学生参与研究。研究人员将邀请博士生、本科少数民族学生以及高中生参与这项实验和理论相结合的研究，旨在通过全面了解未来2D设备中热传输的主要贡献和局限性来造福社会。这项提议的主要目标是让社区更深入地了解二维非均质材料中通过各种结点和界面的散热和热量排出动力学所设置的极限。该团队的目标是通过材料合成和设备级实验、原子级表征、热输运和声子光谱、理论建模和计算研究的紧密结合，建立一个多尺度的热输运研究。变革性的合成/制造方法，如化学气相沉积和原子层沉积，将被用来制造感兴趣的异质结构，作为任何电子器件的基本部件。合成结构的面内和面外导热系数将使用定制设计的电测温平台进行测量。此外，还将利用外差瞬变光栅技术测量载热声子的平均自由程(MFP)分布和导热系数的长度尺度关系。在高功率工作条件下，将进行原位扫描热显微镜表征，以研究选定的半导体2D材料在其接触金属电极上的自热。原子分辨扫描电子显微镜将用于表征2D材料的界面和表面。表征结果将指导分子动力学模拟预测界面和晶界的原子结构，并量化小尺度结构变化对材料热输运性质的影响。热输运，包括声子MFP的全谱，将使用包括本征声子散射和界面散射的声子Boltzmann输运方程来计算。声子MFP分布的模拟结果和玻尔兹曼输运计算将与瞬时光栅测量和器件级数据相比较，以建立二维非均匀材料中热耗散的预测模型。拟议的研究具有变革的潜力，并在许多研究领域具有很高的相关性。这项工作的广泛影响将对从热管理的角度为未来的电子学/光电子学设计新类别的2D异质材料具有重要意义。