Uncooled Infrared Radiation Focal Plane Array with Low Noise Pixel Driving Circuit

Abstract

We have analyzed the dominant noise sources in the driving circuit of an uncooled infrared radiation focal plane array fabricated on a silicon-on-insulator (SOI) substrate by 0.35 μm CMOS technology and bulk-micromachining. We found no noise property of SOI-MOSFET inferior compared to those of NMOSs formed on SOI and bulk substrate, respectively. In addition, we reduced the total noise of the sensor chip by designing the current source NMOS sufficiently large, and optimized the operating current of pixel pn-junctions.

Low-Cost Microbolometer Type Infrared Detectors

“…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.…”