A Novel Three-Dimensional Thin-film Thermoelectric Generator for Wearable Applications

职务名称：一种新型的高性能薄而轻的三维热电发电机收集人体热量为可穿戴设备供电非技术摘要：热电发电机可以将人体热量转换为电能，为低功率电子设备提供连续的能源。小而轻的热电发电机可以集成到可穿戴设备中，使无电池设备成为现实。 研究表明，很大一部分用户在几个月后停止使用他们的可穿戴设备，部分原因是需要频繁充电。解决方案是使这种可穿戴设备自供电，无需充电或更换电池。这样的壮举也将使可穿戴设备在临床应用中的使用成为可能。例如，自供电设备将允许医生在老年患者出院后持续监测他们的状态。除了健康和健康监测之外，自供电传感器的连接网络还可以为工业制造、精准农业、环境监测、测量和土木工程以及智能和互联家庭的决策提供信息。 到目前为止，商业热电设备的制造方式与50年前类似。它们体积庞大，每个设备只有几十个毫米级元件，因此，它们的输出电压太低（几毫伏），并且它们的形状因子不适合可穿戴应用。本研究的目的是制作一种新颖的器件结构，使每平方厘米数千个微尺度热电元件的集成和堆叠成为可能。这种新的设备很薄，重量很轻，可以从身体热量中产生几伏的电压，适合各种可穿戴应用。此外，制造过程将是依赖于成熟的行业兼容工艺的晶圆级，这使其成为商业化的可行技术。技术摘要：本研究的目的是开发一种新型的三维薄膜热电发电机，适用于人体热量收集和可穿戴传感器和电子设备供电。传统的热电发电机仅由十几个毫米级元件组成，无法从体温中产生足够的电压。提出了一种新的器件结构，使得能够制造由每平方厘米数千个微尺度热电元件组成的高效薄膜热电器件。因此，新器件可以产生1000倍的输出电压。它实现了这一性能增强得益于一个全新的设备架构，它允许堆叠的薄膜元件在一个三维结构，并自真空密封，最大限度地减少寄生热损失。该方法不仅能够实现真空封装，而且还允许制造其中热电长度与沉积膜的厚度无关的薄膜器件。这是对传统结构的显著改进，因为可以独立于膜厚度实现元件的电阻和热阻的优化。工业兼容，晶圆级微制造工艺将用于制造廉价的硅晶片上的三维热电发电机。制造将依赖于微机电系统集成中使用的成熟工艺和技术。此外，在实现这一目标的过程中，（a）碲化铋基热电器件将在氧化硅/硅衬底上生长并表征，（B）将开发一个全面的三维模型，以更好地理解和优化器件架构并最大限度地减少寄生热损失，以及（c）该器件将针对人体热量收集和可穿戴应用进行表征。

Title: A novel high performance thin and light three-dimensional thermoelectric generator harvesting human body heat for powering wearable devicesNontechnical Abstract:Thermoelectric generators can convert body heat to electrical energy providing a continuous source of energy for low power electronics. Small and light weight thermoelectric generators can be integrated into wearable devices making battery-less devices a reality. Studies have shown that a large fraction of the users stop using their wearables after a few months partly caused by the need for frequent charging. The solution is to make such wearables self-powered eliminating the need for recharging or replacing the batteries. Such a feat would also enable the use of wearables in clinical applications. For instance, self-powered devices would allow physicians to monitor continuously the state of their elderly patients after they are discharged from the hospital. In addition to wellness and health monitoring, connected networks of self-powered sensors could inform decisions in industrial manufacturing, precision agriculture, environmental monitoring, surveying and civil engineering, and of course smart and connected homes. To date, commercial thermoelectric devices are fabricated in similar way as they were made fifty years ago. They are bulky with only dozens of millimeter-scale elements per device, as such, their output voltage is too low (a few milli-volts) and their form factor is not appropriate for wearable applications. The objective of this research is to make a novel device architecture that enables integration and stacking of thousands of microscale thermoelectric elements per centimeter square. The new device is thin and light weight, and can generate several volts from body heat appropriate for various wearable applications. Moreover, the fabrication process will be wafer-scale relying on mature industry compatible processes, which makes it a viable technology for commercialization. Technical Abstract:The objective of this research is to develop a novel three-dimensional thin-film thermoelectric generator suitable for body heat harvesting and powering wearable sensors and electronics. A conventional thermoelectric generator consists of only a dozen of millimeter-scale elements, which cannot generate sufficient voltage from body heat. A novel device architecture is proposed that enables fabrication of high efficiency thin film thermoelectric devices consisting of several thousands of microscale thermoelectric elements per square centimeter. Therefore, the new device can generate 1000X larger output voltage. It achieves this performance enhancement thanks to an entirely new device architecture, which allows stacking of thin film elements in a three-dimensional construction, and self-vacuum-sealing that minimizes parasitic heat losses. The approach not only enables vacuum encapsulation, but also allows making a thin-film device in which the thermoelectric length is independent of the thickness of the deposited film. This is a significant improvement over conventional architectures since optimization of the electrical and thermal resistances of the elements can be achieved independent of the film thickness. Industry compatible, wafer-scale micro-fabrication process will be used to fabricate the proposed three-dimensional thermoelectric generator on inexpensive silicon wafers. The fabrication will rely on mature processes and techniques used in micro-electro-mechanical-systems integration. Furthermore, in the path to achieving this goal, (a) bismuth telluride based thermoelectrics will be grown on silicon oxide/silicon substrate and characterized, (b) a comprehensive three-dimensional model will be developed to better understand and optimize the device architecture and minimize the parasitic heat losses, and (c) the device will be characterized for human body heat harvesting and wearable applications.