Journal of Sensor Science and Technology (센서학회지)

The Korean Sensors Society (한국센서학회)
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Fabrication of Silicon Window for Low-price Thermal Imaging System

저가형 열영상 시스템을 위한 실리콘 윈도우 제작

  • Sung, Byung Mok (School of electronics engineering, Kyungpook National University) ;
  • Jung, Dong Geon (School of electronics engineering, Kyungpook National University) ;
  • Bang, Soon Jae (School of electronics engineering, Kyungpook National University) ;
  • Baek, Sun Min (School of electronics engineering, Kyungpook National University) ;
  • Kong, Seong Ho (School of electronics engineering, Kyungpook National University)
  • Received : 2015.06.29
  • Accepted : 2015.08.04
  • Published : 2015.07.31
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Abstract

An infrared (IR) bolometer measures the change of resistance by absorbing incident IR radiation and generates a signal as a function of the radiation intensity. Since a bolometer requires temperature stabilization and light filtering except for the infrared rays, it is essential for the device to be packaged meeting conditions that above mentioned. Minimization of heat loss is needed in order to stabilize temperature of bolometer. Heat loss by conduction or convection requires a medium, so the heat loss will be minimized if the medium is a vacuum. Therefore, vacuum packaging for bolometer is necessary. Another important element in bolometer packaging is germanium (Ge) window, which transmits IR radiation to heat the bolometer. To ensure a complete transmittance of IR light, anti-reflection (AR) coatings are deposited on both sides of the window. Although the transmittance of Ge window is high for IR rays, it is difficult to use frequently in low-price IR bolometer because of its high price. In this paper, we fabricated IR window by utilizing silicon (Si) substrate instead of Ge in order to reduce the cost of bolometer packaging. To enhance the IR transmittance through Si substrate, it is textured using Reactive Ion Etching (RIE). The texturing process of Si substrate is performed along with the change of experimental conditions such as gas ratio, pressure, etching time and RF power.

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References

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