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兴趣，因为它们可以将机械、电子、生物体等的操作产生的一些不需要的废热回收为有用的电力。限制热电装置广泛使用的主要挑战之一是难以使具有优异热电性质的材料适应工业和经济规模化生产。理想的情况是以类似于商业集成电路技术中硅的工业生产方式制造热电发电机。最近，人们发现硅以非常小的线（称为纳米线）的形式具有良好的热电特性，并且可以与现有的硅电子器件集成。该项目的主要目标是确定如何实现这一潜力，并开辟一条将具有有用性能特性的硅纳米线热电发电机集成到现有工业硅技术中的路线。可扩展到工业生产的高效硅集成电路热电器件的开发将为工业开辟许多具有直接和未来效益的应用，包括通过收集废热来提高大规模电子设备中的能量效率、调节高功率电子设备中的温度积累以及建立环境"绿色“方式来为微电子电路供电。这项研究还为本科生和研究生提供了一个独特的跨学科培训机会。该项目将使学生接触到工业的视角和研究方法，这将对学生和社会特别有价值，当他们进入劳动力市场时。集成电路热电（TE）发电机（IC TEG）作为一种芯片上的小尺寸方式来激励或驱动微电路和传感器或以局部方式调节芯片温度具有令人信服的重要性。当前大多数TE研究的重点是开发具有高TE品质因数ZT的材料。广泛研究的高ZT材料（例如Bi 2 Te 3）具有略大于1的ZT，但与工业Si处理不相容，因此难以以商业规模化的方式并入作为微电子TEG。最近发现Si纳米线（SiNW）可以具有高达0.6的ZT。虽然这开辟了一条通往硅TEG的道路，但SiNW的ZT对制造高度敏感，在实际情况下通常为约0.3。然而，TEG将温差转换成电功率的程度往往不仅受到ZT的限制，而且受到降低热输入和电功率输出的寄生器件阻抗的限制。这些阻抗可以在Si处理中设计和控制，因此通过仔细优化电阻抗和热阻抗匹配，可以使SiNW TEG的性能与较高ZT材料竞争。该项目旨在最大限度地提高基于SiNW的IC TEG电压/功率生成，不仅通过材料方法，而且通过理解，控制和优化TEG设计，寄生损耗和阻抗匹配方面。要研究的SiNW TEG电路是用基线工业硅技术制造的，因此可以以高度紧凑、单片和受控的方式集成到更大的电路中。主要目标是展示对微电子行业有用的SiNW IC TEG，并以商业可扩展的方式制造。

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.