Journal of Sensor Science and Technology (센서학회지)

The Korean Sensors Society (한국센서학회)
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Micro flow sensor using polycrystalline silicon carbide

다결정 실리콘 카바이드를 이용한 마이크로 유량센서

  • Lee, Ji-Gong (Electrical Engineering and Computer Science, Case Western Reserve University) ;
  • Lei, Man I (Electrical Engineering and Computer Science, Case Western Reserve University) ;
  • Lee, Sung-Pil (Department of Electronic Engineering, Kyungnam University) ;
  • Rajgopal, Srihari (Electrical Engineering and Computer Science, Case Western Reserve University) ;
  • Mehregany, Mehran (Electrical Engineering and Computer Science, Case Western Reserve University)
  • Published : 2009.03.31
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Abstract

A thermal flow sensor has been fabricated and characterized, consisting of a center resistive heater surrounded by two upstream and one downstream temperature sensing resistors. The heater and temperature sensing resistors are fabricated from nitrogen-doped(n-type) polycrystalline silicon carbide(poly-SiC) deposited by LPCVD(low pressure chemical vapor deposition) on LPCVD silicon nitride films on a Si substrate. Cavities were etched into the Si substrate from the front side to create suspended silicon nitride membranes carrying the poly-SiC elements. One upstream sensor is located $50{\mu}m$ from the heater and has a sensitivity of $0.73{\Omega}$/sccm with ${\sim}15\;ms$ rise time in a dynamic range of 1000 sccm. N-type poly-SiC has a linear negative temperature coefficient and a TCR(temperature coefficient of resistance) of $-1.24{\times}10^{-3}/^{\circ}C$ from room temperature to $100^{\circ}C$.

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