Phtalocyanine based integrated gas sensor

This paper presents the layout and the technological steps for an interdigitally integrated capacitor used for gas detection. Silicon micromachining technology is applied for manufacturing the sensor substrate. The sensitive layer used is phthalocyanine (Pc) deposed by EDL (evaporated dyes layers technique). Many solutions were found using the phthalocyanine derivatives deposition technique. Considering the different sensitivities of phthalocyanines derivatives, we obtained different gas sensors. The copper phthalocyanine (Cu Pc) and nickel phthalocyanine (Ni Pc) have been investigated for NO_x detection. The measurement of sensors for NO_x and NH₃ detection are presented as concentration versus impedance. The microsensor testing structures deposited with phthalocyanines were investigated by impedance measurements in a vacuum chamber controlled by a gas analyzer. The measurements were made at room temperature but a medium temperature is applied (< 200°C) after measurement, for cleaning the material in order to reuse the sensor. The sensor is integrated, MOS compatible, cheap, easy to use and has low power consumption.