Progress toward high-performance thermopile imaging arrays

摘要: Thermopiles are uncooled, broadband detectors that require no chopper or temperature stabilizer. Their wide operating- range, lack of stabilization, and radiometric accuracy make thermopiles well suited for some space-based scientific imaging applications. These may also offer advantages over bolometers night vision. Previous work at JPL has produced thermopile linear arrays with D* values 10 9 cmHz 1/2 /W by combining high- performance thermoelectric materials Bi-Te Bi-Sb-Te bulk micromachining processes. To date, however, 2-D have demonstrated only moderate performance. The purpose the present is to improve substantially a unique pixel structure low-noise readout circuitry. initial goal 128 X array single multiplexed analog output stream, system (including noise) /W, focal-plane power dissipation 20 mW. 100 micrometers square been 2 8 response times 4 ms. Models predict optimized detectors. Modeling preliminary design shows that, expected detector resistance kΩ, total noise will be 50% higher than Johnson noise. CMOS test chips containing front-end circuits presently display about 2.5 modeled 0.6 μW per pixel.