A Low-Cost 128 $\times$ 128 Uncooled Infrared Detector Array in CMOS Process
- 7 February 2008
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in Journal of Microelectromechanical Systems
- Vol. 17 (1) , 20-30
- https://doi.org/10.1109/jmems.2007.910235
Abstract
This paper discusses the implementation of a low-cost 128 times 128 uncooled infrared microbolometer detector array together with its integrated readout circuit (ROC) using a standard 0.35 mum n-well CMOS and post-CMOS MEMS processes. The detector array can be created with simple bulk-micromachining processes after the CMOS fabrication, without the need for any complicated lithography or deposition steps. The array detectors are based on suspended p+-active/n-well diode microbolometers with a pixel size of 40 mum times 40 mum and a fill factor of 44%. The p+-active/n-well diode detector has a measured dc responsivity (R) of 4970 V/W and a thermal time constant of 36 ms at 50 mtorr vacuum level. The total measured rms noise of the diode type detector is 0.69 muV for an 8 kHz bandwidth, resulting in a detectivity (D*) of 9.7 times 108 cm ldr Hz1/2/W. The array is scanned by an integrated 32-channel parallel ROC including low-noise differential preamplifiers with an electrical bandwidth of 8 kHz. The 128 times 128 focal plane array (FPA) has one row of infrared-blind reference detectors that reduces the effect of FPA fixed pattern noise and variations in the operating temperature relaxing the requirements for the temperature stabilization. Including the noise of the reference and array detectors together with the ROC noise, the fabricated 128 times 128 FPA has an expected noise equivalent temperature difference (NETD) value of 1 K for f/1 optics at 30 frames/s (fps) scanning rate. This NETD value can be decreased to 350 mK by improving the post-CMOS fabrication steps and increasing the number of readout channels.Keywords
This publication has 34 references indexed in Scilit:
- A low-cost 64×64 uncooled infrared detector array in standard CMOSPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2004
- Low-cost uncooled infrared detectors in CMOS processSensors and Actuators A: Physical, 2003
- Low-cost uncooled infrared detector arrays in standard CMOSPublished by SPIE-Intl Soc Optical Eng ,2003
- A low-cost uncooled infrared microbolometer detector in standard CMOS technologyIEEE Transactions on Electron Devices, 2003
- A low cost uncooled infrared microbolometer focal plane array using the CMOS n-well layerPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2002
- Low-cost small-pixel uncooled infrared detector for large focal plane arrays using a standard CMOS processPublished by SPIE-Intl Soc Optical Eng ,2002
- Low-noise readout circuit for uncooled infrared FPAPublished by SPIE-Intl Soc Optical Eng ,2000
- An integrated thermopile structure with high responsivity using any standard CMOS processSensors and Actuators A: Physical, 1998
- Micromachined thermally isolated circuitsSensors and Actuators A: Physical, 1997
- Laminated high-aspect-ratio microstructures in a conventional CMOS processSensors and Actuators A: Physical, 1996