CAREER: Advanced Microfabricated Magnetics for Power and RF Applications

通过世界各地研究人员和制造商的共同努力，微处理器的能力继续呈指数级增长，正如戈登·摩尔在1965年所预测的那样。在许多领域取得的进展将继续支持摩尔定律。但一个新的障碍隐约可见：为非常高电流、非常低电压的处理器供电。在以足够的稳定性和足够快的响应时间提供这种电力方面的困难为行业赢得了电力墙的绰号。该项目将开发微制造磁性元件的创新，使微处理器能够以远远超过正在研究的其他技术的能力提供电力，并将为在广泛的应用中使用先进的磁学奠定基础。未来的微处理器通常需要大约100 A的电源电流。通过将电源电压调整到较低的水平来缓解电力需求，但由此产生的低阻抗使稳定的电力输送变得更加困难。一个小尺寸、快速响应的电源转换器需要紧邻处理器。便携式电池供电的系统对效率和尺寸施加了更严格的限制。改进的电感对于满足这些要求至关重要。最先进的电感仍然是功率转换器中最大和最昂贵的组件，它们限制了效率和响应时间。必须应用一种新技术--例如微细加工。但现有的微细加工磁性材料表现出效率低、功率密度低或两者兼而有之的情况。该项目将引入几种创新方法，将极大地提高性能。新的磁性材料将实现低磁滞和涡流损耗，但允许在5-20 MHz范围内以高磁通密度运行。这些特性将通过使用由纳米磁性金属颗粒组成的复合材料在陶瓷基质中获得，通过真空蒸发沉积。在这些材料中，陶瓷将绝缘颗粒以防止涡流，而超细颗粒将降低矫直力和磁滞损耗。此外，一种新提出的制造工艺将使用各向异性硅蚀刻和其他微制造技术来形成配置优化的低阻抗大电流应用的电感。其结果将是更高的功率密度和效率，以及简化的工艺流程，从而简化磁性材料的沉积。使用这种新材料和工艺的电感将被制造和测试，并将与包括英特尔公司和Volterra在内的工业合作伙伴合作开发应用程序，这些合作伙伴将在电路实施方面进行合作并提供资金支持。新的磁性技术将有广泛的应用，包括在其他系统中的功率转换和射频通信电路的电感；新的磁性材料预计将具有良好的性能，频率高达1 GHz。该项目旨在实现研究和教育之间的协同。包括一年级本科生、高水平本科生和博士生在内的学生将积极参与研究计划。为了应对与为本科生提供有意义的研究经验相关的重大挑战，成功的、经过验证的本科生研究项目将与学生团队的改进相结合。该研究计划将通过利用微制造工作提供的独特机会，为本科生提供在适当技能水平上进行有用和令人满意的工作的机会。推广和课程创新将有助于培养下一代工程师。让高中生和初中生参加的外展活动将吸引他们进入工程学；让本科生体验现实世界解决问题的乐趣的课程将激励他们继续学习；基于现代应用的电力电子和机电能量转换的精简课程将鼓励他们学习这一关键领域。

9875204SullivanThrough the combined efforts of researchers and manufacturers all over the world, the capabilities of microprocessors continue to grow exponentially as predicted by Gordon Moore in 1965. Progress in numerous fields is on track to continue to uphold Moore's Law. But a new obstacle looms: powering very high-current, very low-voltage processors. The difficulties in delivering this power with sufficient stability and fast enough response time have earned the industry nickname the Power Wall. This project will develop innovations in microfabricated magnetic components that will allow microprocessor power delivery with performance well beyond the capabilities of other techniques now being studied, and will lay the foundations for advanced magnetics in a wide range of applications.Future microprocessors will typically require supply currents on the order of 100 A. The power requirement is mitigated by scaling supply voltages to lower levels, but the resulting low impedance makes stable power delivery more difficult. A small-size, fast-response power converter will need to be located immediately adjacent to the processor. Portable, battery powered systems impose even more stringent efficiency and size constraints. Improved inductors are critical for meeting these requirements. State-of-the-art inductors remain the largest and most expensive components in power converters, and they limit the efficiency and response time. A new technology-such as microfabrication-must be applied. But existing microfabricated magnetics exhibit poor efficiency, poor power density, or both.This project will introduce several innovative approaches that will dramatically boost performance. New magnetic materials will achieve low hysteresis and eddy-current losses, yet allow operation with high flux density in the 5-20 MHz range. These properties will be obtained by using composite materials comprising nanoscale particles of magnetic metal in a ceramic matrix, deposited by vacuum evaporation. In these materials, the ceramic will insulate the particles to prevent eddy currents, while the ultrafine particles will reduce coercivity and hysteresis loss. In addition, a newly proposed fabrication process will use anisotropic silicon etching and other microfabrication techniques to form inductors in a configuration optimized for low-impedance high-current applications. The result will be higher power density and efficiency with a streamlined process flow that will simplify magnetic material deposition. Inductors using the new material and process will be fabricated and tested, and applications will be developed in cooperation with industrial partners including Intel Corp. and Volterra, who will collaborate on implementation of circuits and provide financial support.The new magnetics technology will have a broad range of applications including power conversion in other systems and inductors for RF communications circuits; the new magnetic materials are expected to have good properties up to frequencies on the order of 1 GHz.The project is designed to capture synergy between research and education. Students including first-year undergraduates, upper-level undergraduates, and Ph.D. candidates will be actively involved in the research program. To meet the significant challenges associated with providing undergraduates with a meaningful research experience, successful, proven programs in undergraduate research will be combined with refinements in student teaming. The research program will be structured to provide opportunities for useful and satisfying work at appropriate skill levels for undergraduates, by taking advantage of the unique opportunities afforded by work in microfabrication.Outreach and curriculum innovation will help develop the next generation of engineers. Outreach activities involving high-school and junior-high-school students will attract them to engineering; courses that let undergraduates sample the fun of real-world problem solving will inspire them to continue; and a streamlined class in power electronics and electromechanical energy conversion based on modem applications will encourage them to study this critical area.***