ELABORATION AND TESTS OF MICROELECTRONICALLY DESIGNED GAS SENSORS WITH PHTHALOCYANINE SENSITIVE LAYERS

Microsens has developed miniaturized integrated semiconductor gas sens ors using standard microelectronic technologies; these sensors include a semiconducting metal oxide layer (SnO2, Nb2O5) and an integrated he ater on a silicon substrate. The selectivity and sensitivity of the de vices to oxidizing or reducing gases depend on the metal oxide, on its doping and on the selection of an appropriate working temperature. Re cently, in collaboration with LASMEA, the same microelectronic device has been used to develop gas sensors on which the metal oxide layer is replaced by a phthalocyanine thin film. Phthalocyanines are known to be sensitive to oxidizing gases at ppm concentrations, and the specifi city of their responses makes them potential gas sensors or complement ary elements of SnO2 in the realization of multi-array integrated gas sensors. This papers describes the successive steps of the manufacturi ng of miniaturized phthalocyanine gas sensors and shows that depositio n of phthalocyanine thin films by evaporation is compatible with micro electronic technologies. Responses of CuPc and AlPcF(n) films to NO2, HCl and CO are reported. Each gas induces conductivity variations on b oth phthalocyanines; these variations are qualitatively and quantitati vely different depending on the gas-phthalocyanine pair.