GOALI: Integrated Circuit Silicon Nanowire Thermoelectric Generators for On-chip Micropower Generation

热电发电机对社会具有巨大的科学和技术价值，因为它们可以将机械、电子、生物等运行产生的一些不需要的废热回收利用，转化为有用的电力。限制热电设备广泛使用的主要挑战之一是难以将具有优异热电性能的材料应用于工业和经济上可扩展的生产。理想的做法是以一种工业生产的方式制造热电发电机，类似于商业集成电路技术中使用硅的方式。最近，人们发现一种非常小的导线(称为纳米线)形式的硅具有良好的热电特性，并可能与现有的硅电子设备集成在一起。该项目的主要目标是确定如何发挥这一潜力，并开辟一条将具有有用性能特征的硅纳米线热电发电机集成到现有工业硅技术中的途径。可扩展到工业生产的高效硅集成电路热电器件的开发将开辟许多立即和未来对工业有益的应用，包括通过收集废热来提高大规模电子产品的能效，调节大功率电子产品的温度积累，以及建立一种环保的微电子电路供电方式。这项研究也为本科生和研究生提供了一个独特的有价值的跨学科培训机会。这个项目将使学生接触到工业视角和研究方法，当他们进入劳动力大军时，这将对学生和社会都特别有价值。集成电路热电(TE)发生器(IC TEG)作为一种芯片上、小尺寸的方式来激励或启动微电路和传感器或以局部方式调节芯片上的温度，具有令人信服的重要性。目前TGS的大多数研究都集中在开发具有高TE优值系数ZT的材料上。被广泛研究的高ZT材料，如Bi2Te3，其ZT略大于1，但与工业硅加工不兼容，因此很难以商业可扩展的方式并入微电子TAG。最近发现硅纳米线(SiNW)的ZT可高达0.6。虽然这开辟了一条通往硅台板的道路，但SiNW的ZT对制造高度敏感，在实际环境中通常为0.3。然而，TEG将温差转换成电能的程度不仅受到ZT的限制，还受到降低热输入和电能输出的寄生设备阻抗的限制。这些阻抗可以在硅工艺中设计和控制，因此，通过仔细优化电阻和热阻抗匹配，SiNW TEGS的性能可以与更高的ZT材料竞争。该项目不仅通过简单的材料方法，而且通过了解、控制和优化TEG设计、寄生损耗和阻抗匹配方面，寻求最大化基于SiNW的IC TEG电压/发电。被研究的SiNW TEG电路采用基线工业硅技术制造，因此可以以高度紧凑、单片和可控的方式集成到更大的电路中。主要目标是展示对微电子工业有用并以商业可扩展的方式制造的SiNW IC TEG。

Thermoelectric generators are of great scientific and technological interest to society because they can recycle some of the unwanted waste heat generated from the operation of machinery, electronics, living organisms, etc. back into useful electrical power. One of the major challenges limiting widespread use of thermoelectric devices is the difficulty in adapting materials having excellent thermoelectric properties into industrially and economically scalable production. The ideal would be to make thermoelectric generators in an industrial production manner similar to what is done with silicon in commercial integrated circuit technology. Recently it was discovered that silicon in the form of a very small wire (called a nanowire) has good thermoelectric characteristics and can be potentially integrated with existing silicon electronics. The main goal of this project is to determine how to fulfill that potential and pioneer a route towards integrating silicon nanowire based thermoelectric generators having useful performance characteristics into existing industrial silicon technology. The development of efficient silicon integrated circuit thermoelectric devices scalable to industrial production will open up numerous applications of immediate and future benefit to industry, including improving energy efficiency in large scale electronics by harvesting waste heat, regulating temperature build up in high power electronics, and establishing an environmentally ¡°green¡± way to power microelectronic circuits. This research also provides a uniquely valuable cross-disciplinary training opportunity for undergraduate and graduate students. This project will expose students to an industrial perspective and approach to research, which will be particularly valuable to both students and society when they enter the workforce.Integrated circuit thermoelectric (TE) generators (IC TEG) have compelling importance as an on-chip, small form factor way to energize or actuate microcircuits and sensors or regulate on-chip temperature in a localized manner. Most current research in TEGs focuses on developing materials having a high TE figure-of-merit ZT. Widely studied high ZT materials such as Bi2Te3 have ZT slightly larger than 1 but are incompatible with industrial Si processing and thus are difficult to incorporate as microelectronic TEGs in a commercially scalable manner. Recently it was found that Si nanowires (SiNWs) can have ZT up to 0.6. While this opens a route towards silicon TEGs, the ZT of SiNWs is highly sensitive to fabrication, being typically ¡Ü 0.3 in practical circumstances. However, how well a TEG converts temperature difference into electrical power tends to be limited not only by ZT but by parasitic device impedances that degrade heat input and electrical power output. These impedances can be designed and controlled in Si processing, so the performance of SiNW TEGs could be made competitive with higher ZT materials by carefully optimizing the electrical and thermal impedance matches. This project seeks to maximize SiNW based IC TEG voltage/power generation not simply through a materials approach but by understanding, controlling, and optimizing TEG design, parasitic losses, and impedance matching aspects. The SiNW TEG circuits to be studied were fabricated with baseline industrial silicon technology and thus can be integrated into larger circuits in a highly compact, monolithic, and controlled manner. The main goal is to demonstrate SiNW IC TEGs useful to the microelectronics industry and fabricated in a commercially scalable manner.