Fabrications and Characteristics of Infrared Sensor Composed of λ/4 Absorbing Structure for the Application of NDIR CO2 Gas Sensor

λ/4 흡수층 구조를 갖는 NDIR 이산화탄소 가스센서용 적외선 센서의 제조 및 특성

  • 이성현 (한양대학교 금속재료공학과) ;
  • 남태운 (한양대학교 금속재료공학과)
  • Published : 2008.11.01


A noble infrared $\lambda/4$ absorbing structure using metal reflector was studied for uncooled infrared sensors. This paper described the design and the fabrication of IR uncooled detectors which were composed of 21 by 21 elements using the surface micromachining technology. The characteristics of the array were investigated in the spectral region of 4.26 ${\mu}m$. The fabricated detectors exhibited the thermal mass of $9.75\times10^{-9}$ J/K, the thermal conductance of $1.31\times10^{-6}$ W/K, the thermal time constant of 7.4 ms, the responsivity of $1.07\times10^5$ V/W and the detectivity of $1.04\times10^9$ $cmHz^{1/2}/W$, at the chopper frequency of 10 Hz and the bias current of 9.22${\mu}A$. Finally the absorptance efficiency of $\lambda/4$ absorbing structure was about 23.2 % higher than that of absence absorbing structure.


  1. B. E. Cole, "Monolithic two-dimensional arrays of micromachined microstructures for infrared applications", Proceedings of the IEEE, Vol. 86, p. 1679, 1998
  2. Paul W. Kruse, "A comparison of the limits to the performance of thermal and photon detector imaging arrays", Infrared Phys. Tech, Vol. 36, p. 869, 1995
  3. H. K. Lee, J. B. Yoon, E. S. Yoon, S. B. Ju, Y.-J. Yong, W. Lee, and S. G. Kim, "A high fill-factor infrared bolometer using micromachined multilevel electrothermal structures", IEEE Trans. Electron Devices, Vol. 46, p. 1489, 1999
  4. L. Dobrzanski, E. Nossarzewska-Orowska, Z. Nowak, and J. Piotrowski, "Micromachined silicon bolometers as detectors of soft X-ray, ultraviolet, visible and infrared radiation", Sensors and Actuators A: Physical, Vol. 60, p. 154, 1997
  5. R. J. Herring and P. E. Howard, "Design and performance of the Ultra 320 by 240 uncooled focal plane array and sensor", SPIE, Vol. 2746, p. 1, 1996
  6. L. Mechin, J.-C. Villegier, and D. Bloyet, "Suspended epitaxial YBaCuO microbolometers fabricated by silicon micro-machining: Modeling and measurements", J. Appl. Phys., Vol. 81, p. 7039, 1997
  7. E. Iborra, M. Clement, L. V. Herrero, and J. Sangrador, "IR uncooled bolometers based on amorphous $GexSi_{1-x}O_y$ on silicon micromachined structures", J. Microelectro Mechanical Systems, Vol. 11, p. 322, 2002
  8. P. L. Richards, "Bolometers for infrared and millimeter waves", J. Appl. Phys., Vol. 76, p. 1, 1994
  9. A. Rogalski, Infrared Detectors, Gordon and Breach Science Publishers, ch. 1, 2000
  10. CRC Handbook, Http://
  11. Paul W. Kruse and David D. Skatrud, "Uncooled infrared imaging arrays and systems", Academic press