INTEGATED MICROSENSORS FOR NITRIC OXIDES DETECTION FOR BIOMEDICAL AND ENVIRONMENTAL APPLICATIONS
C. MOLDOVAN, R. IOSUB, C. BOSCORNEA, L. HINESCU, V. VOICU, M. HINESCU, M. ROBU, M. NISULESCU, M. ION

Abstract. The paper presents the layout and the technological steps for an interdigitally integrated capacitor used for gases 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 as 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 will be presented as concentration versus impedance.
The microsensors 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 be used and has a low power consumption.