Uncooled IRFPA technologies: state of the art and developments at LETI/LIR

摘要

Abstract: Today, large numbers of uncooled IR detector developments are under progress due to the availability of silicon technology that enables realization of low cost 2D IR arrays. Development of such a structure involves a lot of trade-offs between the different parameters which characterize these detectors: (i) IR flux absorption, (ii) measurement of the temperature increase due to the incoming IR flux absorption, (iii) thermal insulation between detector and readout circuit, (iv) readout of thermometer temperature variation. These trade-offs explain the number of different approaches which are under worldwide development. We present a rapid survey of the state of the art through these developments. If the most advance developments are found in the US and Great Britain, it is important to analyze the work which is being done by Japanese companies like MITSUBISHI, NEC,...which are involved since a few years in that area. LETI/LIR has chosen resistive amorphous silicon as thermometer for this uncooled microbolometer development. After a first phase dedicated to the acquisition of the most important detector parameters in order to help the modeling and the technological development, an IRCMOS laboratory model was realized and characterized. It was shown that NETD of 80 mK at f/1, 25 Hz and 300 K background can be obtained with high thermal insulation. !11