Characterization of area arrays of microbolometer-based un-cooled IR detectors without using ROIC

We present the characterization of microbolometer area arrays being developed for IR imaging applications. Here, we propose a technique that does not use readout integrated circuit for accessing detector array elements for characterization, which is useful for initial detector technology development. The technique is based on a connection scheme that uses two levels of metal lines in a row–column fashion, thereby, reducing the number of pads and therefore the fan-out complexity from N × M to N + M for an array of N × M detectors. The resulting networked structure has been analyzed and the technique has been developed for extracting back the actual signal and noise values from the measured data. We have implemented this technique on a set of 16 × 16 arrays of Ti-microbolometers developed at our laboratory. However, it may be extended to other types as well. The measurement on these arrays and extraction of various performance parameters are discussed here. The results of detailed characterization show that the average detectivity is about 1.44 × 108 Jones, TCR is 0.27%, thermal time constant is 9.91 ms and thermal conductivity is 0.16 μW/K in these arrays. These values are very close to the design values.