The Effect of Area Density of Polysilicon Thermocouples on Thermoelectric Performance
Thermoelectric energy generators (TEGs) that can convert body heat into electricity are considered most promising to drive wearable devices. Many TEG designs with a polysilicon thermocouple have been proposed for implementation in high-yield semi-conductor foundry services. This study shows that the...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-02-01
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| Series: | Sensors |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1424-8220/25/4/1098 |
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| Summary: | Thermoelectric energy generators (TEGs) that can convert body heat into electricity are considered most promising to drive wearable devices. Many TEG designs with a polysilicon thermocouple have been proposed for implementation in high-yield semi-conductor foundry services. This study shows that the area density, defined by the number of thermocouples per mm<sup>2</sup>, is a better index than the fill factor in evaluating TEG performance. The effects of thermocouple length, width, and spacing (between the adjacent thermocouples) on area density, and hence on TEG performance, are analyzed. For a TEG with 33 × 1 μm (length × width) co-planar thermocouples (P- and N-thermoleg side by side) and 1 μm spacing between two adjacent thermocouples, the area density is 4902 thermocouples per mm<sup>2</sup> and it can deliver a 0.110 μW/cm<sup>2</sup>K<sup>2</sup> power factor and a 12.906 V/cm<sup>2</sup>K voltage factor. The performance can be improved further by 57 × 1 μm stacked thermocouples (P-thermoleg above N-thermoleg) with a higher area density 8621 to achieve results of 0.110 μW/cm<sup>2</sup>K<sup>2</sup> and 22.638 V/cm<sup>2</sup>K. Such a high area density not only increases TEG performance, but also improves the DC–DC converter efficiency. A 5 × 5 mm<sup>2</sup> TEG chip with co-planar or stacked thermocouples is shown to deliver above 3 μW and over 3 V when operating at a 10 °C temperature difference. |
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| ISSN: | 1424-8220 |