A free-standing microthermopile infrared detector with a responsivity of 2.5 V/W at 10.6 μm wavelength and a time constant of 20 μs is described. This device is a radiation thermopile in which the hot junctions are thermally isolated from the substrate by making them free-standing. The small thermal mass and good thermal isolation of the hot junctions allows them to heat up when radiation is incident on them, while the cold junctions in contact with the substrate remain at the ambient temperature. The microthermopile is fabricated using silicon micromachining technology and consists of 20 copper-constantan thermocouples connected in series. The performance of the device in the 1 - 12 μm wavelength range is also reported.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering