Background Limited Focal Plane Array Assembly
The thermoelectric detector comprises an infrared absorber pixel structure supported by two electrically connected beams made of a thermoelectric material. One end of the thermoelectric beam connects to the infrared absorber pixel structure; the other end connects to the substrate. The detector comprises a microlens for collecting and focusing infrared radiation on the detector. Infrared radiation is incident on the infrared absorber pixel structure results in a temperature gradient along the length of the thermoelectric legs, and generating an electrical voltage proportional to the gradient. A low noise SIGe BiCMOS readout integrated circuit is coupled to the detector to provide a background limited detector having improved detectivity.
1 . A detector assembly comprising:
a thermoelectric detector comprising an infrared absorber pixel structure comprising a pixel surface area,
the infrared absorber pixel structure coupled to at least one thermoelectric structure at a hot junction,
a microlens element configured to collect and focus infrared energy of a predetermined spectrum upon the pixel surface area, and,
a read out integrated circuit.
2 . The device of claim 1 wherein the read out integrated circuit comprises a SiGe BiCMOS readout integrated circuit fabricated in a set of SiGe BiCMOS semiconductor processing steps coupled to the at least one thermoelectric structure at a cold junction.
3 . The device of claim 1 wherein the at least one thermoelectric structure comprises at least one of bismuth-telluride, antimony-telluride, lead telluride, polysilicon, germanium, skutterudite, a nano-composite material, and a super-lattice structure.
4 . The device of claim 1 wherein the substrate comprises a reflector.
5 . The device of claim 1 wherein the first distance is substantially a quarter-wavelength of a pre-selected detector wavelength, and wherein the infrared absorber pixel structure and the substrate are configured to act as a quarter-wave resonant cavity.
6 . The device of claim 1 further comprising a vacuum enclosure coupled to the substrate to thereby enclose the infrared absorber pixel structure.
7 . A focal plane array assembly comprising a plurality of detector elements wherein the plurality of detector elements each comprise:
a thermoelectric detector comprising an infrared absorber pixel structure comprising a pixel surface area,
the infrared absorber pixel structure coupled to at least one thermoelectric structure at a hot junction,
a microlens element configured to collect and focus infrared energy of a predetermined spectrum upon the pixel surface area, and,
a read out integrated circuit.
8 . The assembly of claim 7 wherein the read out integrated circuit, comprises a SiGe BiCMOS readout integrated circuit fabricated in a set of SiGe BiCMOS semiconductor processing steps coupled to the at least one thermoelectric structure at a cold junction.
9 . The device of claim 7 wherein the at least one thermoelectric structure comprises at least one of bismuth-telluride, antimony-telluride, lead telluride, polysilicon, germanium, skutterudite, a nano-composite material, and a super-lattice structure.
10 . The device of claim 7 wherein the substrate comprises a reflector.
11 . The device of claim 7 wherein the first distance is substantially a quarter-wavelength of a pre-selected detector wavelength, and wherein the infrared absorber pixel structure and the substrate are configured to act as a quarter-wave resonant cavity.
12 . The device of claim 7 further comprising a vacuum enclosure coupled to the substrate to thereby enclose the infrared absorber pixel structure.