Micromachined chemoresistive sensors for CO and CH4 detection

The paper presents the layout and the technological steps for chemo resistive gas sensors silicon based for CO and CH₄ detection. The sensitive layers used as sensor active materials are polymers: polyaniline and polytiophene. The polymers have been deposited from liquid phase, by dropping on the active area of the silicon substrate sensor. The microsensors deposited with polyaniline or polytiophene were investigated by resistance measurements in a vacuum chamber controlled by the computer. The measurements of sensors for CO and CH₄ detection was presented as resistance versus time. The silicon sensors present the advantages of miniaturization, reproducibility, low power consumption and high sensitivity. The realisation of gas microsensors on silicon using the micro machining techniques was presented from point of view of design and micromachining steps.