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MOS Sensor for Detection of NH3 and H2 Gases

Authors : Vinod Kumar



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Abstract

Due to the increased industrialization, emission of green house gases, environment protection becomes an important issue for earth. Therefore, it is necessary to monitoring and controlling of such pollutants by developing an electronic device which may be utilized as a portable detector. The Pt/SiO2/Si MOS sensor was fabricated on p-type <100> Si wafer with thermally grown SiO2 layer of thickness about 100 Å. The platinum (Pt) gate with thickness 350 Å was deposited by vacuum evaporation technique. This sensor is tested towards H2 and NH3. The effect of H2 and NH3 on C-V and sensitivity (s) of the sensor were measured at 25 KHz at room temperature. The sensor exhibited better sensitivity (80%) for both the gases, as compared to reported earlier. This sensor is capable to detect low concentration of H2 and NH3. The minimum concentration of NH3 and H2 is 50 ppm and 250 ppm respectively, at room temperature.
 

Capacitance vs voltage (C-V) response of Pt gate MOS sensor at various concentration of NH3 at room temperature at f =25 KHz

 

Keyword

MOS sensor, Pt, hydrogen, C-V characteristics, NH3, H2.