AUTHENTIC: a very low-cost infrared detector and camera system

Abstract

An Oxide over Titanium metal resistance bolometer technology developed by NMRC (Ireland) has been transferred to the X-FAB UK CMOS foundry at Plymouth, UK. Prototypes of the bolometers have been manufactured in the X-FAB production facility and tests show performance comparable with the NMRC prototypes. The bolometer design has been integrated with a CMOS read-out chip and the first wafers are currently being packaged for evaluation. The development of a low cost thermal imaging camera using the detector is under way. We present an overview of the detector and camera design, together with preliminary results from the detector test programme. The work is partly funded by the European Union IST programme.

Polymer composite based microbolometers

“…The same relation holds true with regards to the organic sensitive layer consisting of pyrolyzed parylene C (Liger, 2006). The NETD value comparison of microbolometers with metallic sensitive layers shows the smallest differences: NETD = 500 mK (microbolometer with sensitive titanium layer: Mansi et al, 2003) as opposed to NETD = 6.7 K (microbolometer pixel with silver composite). These metallic sensitive layers are distinguished by their very low noise levels.…”

Low-Cost Microbolometer Type Infrared Detectors

“… Trends of the pixel size reduction for complementary metal oxide semiconductor (CMOS)-compatible microbolometer infrared (IR) detectors, data taken from (in left-to-right order) [ 12 , 13 , 14 , 15 , 17 , 18 , 19 , 20 , 21 , 22 , 25 , 27 , 28 , 29 , 31 , 32 , 33 , 34 , 35 , 37 , 39 , 40 , 41 , 43 , 46 ]. …”

“…The reason is that the thermal IR detectors are considered to be much slower and less insensitive than the photon IR detectors [ 6 ]. In 1992, both Texas Instruments and Honeywell published their uncooled IRFPAs (infrared focal plane array) based on pyroelectric type and microbolometer type thermal detector, respectively, with fascinating performance [ 10 , 11 ], successfully encouraging a sustained effort to further reduce the pixel size, improve the device performance, and reduce the production cost [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ].…”

“…Not only does the high-integration process lower the production cost of the detectors, but also it provides mature approach with small feature size and high uniformity to benefit the pixel size and the device performance. Especially, the complementary metal oxide semiconductor (CMOS) microbolometer technology is developed for long-wavelength IR (LWIR, 8–14 μm) FPAs via CMOS foundry compatible approaches [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. During the fabrication process, the layer structures of the absorber and the thermal sensor are formed with CMOS process, and then post-CMOS micro-electro-mechanical system (MEMS) process are used to form suspended microbridge structures in purpose of thermal isolation.…”

“…For the CMOS-compatible microbolometer IR detector, one choice is the p-n junction diode which has acceptable properties and compatibility with CMOS process; therefore the silicon-on-insulator (SOI) diode IRFPAs have attracted continuous attention since first reported by Ishikawa et al in 1999 [ 13 ], and have been widely adopted in low-cost commercial IR detectors. Besides, CMOS-compatible metal or semiconductor materials (e.g., aluminum [ 41 , 42 , 43 ], titanium [ 12 , 29 ], polycrystalline silicon [ 44 ], etc.,) have been investigated as another choice as well. Although the SOI diode IRFPA and the CMOS-compatible material microbolometer IRFPA have relative low temperature coefficient, it could be compensated by the high integration and high uniformity.…”