Thermal Transport in Diamond Thin Films: Roles of the Nanostructure and Interfaces

PI：Raj N. Singh，大学CincinnatiCBET-1227788 高性能微处理器和功率半导体器件的散热是微电子行业面临的一项关键挑战。从集成电路 (IC) 散热的最有效方法之一是使用与 IC 接触的高导热材料。在这种背景下，高导热率材料，尤其是已知材料中导热率最高的金刚石，有望用于 IC 的热管理。特别是，本研究的目的是合成层状金刚石薄膜，其中一层（纳米晶金刚石-NCD）将提供光滑的表面以降低界面电阻，第二层（微晶金刚石-MCD）将产生高导热率。该方法将涉及使用内部微波等离子体增强化学气相沉积系统单独合成 NCD 和 MCD 薄膜以及分层 NCD/MCD 薄膜，并使用定制的调制光热反射系统测量热性能。将采用纳米晶种的新方法来降低粗糙度和界面热阻。先进的材料表征技术将用于识别薄膜中的缺陷，并与声子散射的平均自由程相关，以识别控制层状金刚石薄膜中热传输的主要缺陷。这项研究具有重大意义和变革性，因为据我们所知，其结果将是首次全面研究加工对 NCD 和具有改善热性能的层状 NCD/MCD 薄膜中纳米结构、缺陷和热传输机制的影响。这项研究具有巨大回报的潜力，因为热管理在包括光电子、微电子、电力电子和微机电系统在内的多个高科技领域发挥着关键作用。此外，当前重点是保护有限的自然资源用于能源生产，高效的热管理策略将直接节省冷却成本，从而降低能源消耗并对环境产生重大的积极影响。这项研究的一个重要组成部分是对学生和博士后的培训和教育，以及通过期刊出版物和会议演讲传播研究结果。少数族裔/女性和高中生将通过我们大学的多个项目接受指导并接触研究。建议通过教师和学生夏令营对高中进行重大推广。

PI: Raj N. Singh, Univ. of CincinnatiCBET-1227788 Heat dissipation in high performance microprocessors and power semiconductor devices is a critical challenge facing the microelectronics industry. One of the most effective ways to remove heat from integrated circuits (ICs) is to use materials with high thermal conductivity in contact with ICs. In this context, a high thermal conductivity material, especially diamond with the highest thermal conductivity of any known materials, is promising for thermal management of ICs. In particular, the objective of this research is to synthesize layered thin films of diamond in which one layer (nanocrystalline diamond-NCD) will provide smooth surfaces for lower interface resistance and the second layer (microcrystalline diamond-MCD) will result in high thermal conductivity. The approach will involve the synthesis of NCD and MCD films individually and as layered NCD/MCD films using an in-house microwave plasma enhanced chemical vapor deposition system and measuring the thermal properties using a custom-built modulated photothermal reflectance system. A novel approach of nanoseeding will be employed to reduce roughness and interface thermal resistance. Advanced materials characterization techniques will be used to identify defects in the films and relate to mean free path for phonon scattering for identifying the dominant defect controlling thermal transport in layered diamond thin films. The proposed research is significant and transformative because the results will be, to the best of our knowledge, the first comprehensive study on the effect of processing on the nanostructure, defects, and thermal transport mechanisms in NCD and layered NCD/MCD films with improved thermal properties.The proposed research has potentials for enormous payoffs because thermal management plays a critical role in several high-technology areas including optoelectronics, microelectronics, power electronics and microelectromechanical systems. In addition, with the current emphasis on conserving our limited natural resources for energy production, efficient thermal management strategies will result in direct savings in cooling costs leading to lower energy consumption and a significant positive environmental impact. An essential component of this research will be training and education of students and post docs, and dissemination of the results through publications in journals and presentations at conferences. The minority/women and high school students will be mentored and exposed to research through several programs at our university. A significant outreach to high schools is proposed through camps for teachers and students.