| Autor: |
Hans Martin, Claes Mattsson, H-E. Nilsson, Kent Bertilsson, Göran Thungström |
| Rok vydání: |
2008 |
| Předmět: |
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| Zdroj: |
IEEE Sensors Journal. 8:2044-2052 |
| ISSN: |
1530-437X |
| DOI: |
10.1109/jsen.2008.2007679 |
| Popis: |
In the infrared region of the spectrum thermoelectric detectors such as the thermopile are extensively used. These detectors rely on the well-known Seebeck effect, in which there is a direct conversion of thermoelectric differentials into electrical voltage. The temperature difference over thermocouple junctions is in general, created by forming a thin membrane connected to the silicon bulk. In many existing thermopiles, materials such as Si and Si3N4 have been used as membrane. These materials suffer from relatively high thermal conductivity, which lowers the membrane temperature and reduces the sensitivity of the detector. A material such as SU-8 2002 has a much lower thermal conductivity and is applied using standard photolithographic processing steps. This work presents thermal simulations regarding the use of SU-8 2002 as a thermal insulating membrane as compared to Si and Si3N4. The simulation results presented show that the temperature increase in a 5 mum SiO2/SU-8 membrane is about 9% higher than in a 1 mum Si3N4 membrane, despite the membrane thickness being increased by a factor of 5. A thermopile consisting of 196 serially interconnected Ti/Ni thermocouples positioned on a 5 mum SiO2/SU-8 2002 membrane has been fabricated. The sensitivity of the fabricated device has been evaluated in the infrared region, using a 1.56 mum IR laser and a xenon arc lamp together with a monochromator. The measurement results show a sensitivity of approximately 5 V/W over the wavelength range between 900-2200 nm. Measurements performed in a vacuum chamber show that the sensitivity of the detector could be increased by more than a factor of 3 by mounting the detector in a vacuum sealed capsule. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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