J. Goschnick et al., NONUNIFORM SIO2 MEMBRANES PRODUCED BY ION-BEAM-ASSISTED CHEMICAL-VAPOR-DEPOSITION TO TUNE WO3 GAS SENSOR MICROARRAYS, Surface & coatings technology, 109(1-3), 1998, pp. 292-296
Ion beam-assisted chemical vapor deposition (IBAD) has been applied to
prepare non-uniform SiO2 layers to adjust the gas selectivity of meta
l oxide gas sensors integrated in a microarray of 40 WO3 individually
addressable gas sensor elements. SiO2 membranes with a thickness gradi
ent in one direction are applied on microarrays to differentiate initi
ally identical sensor elements with respect to their gas response. The
analysis with X-ray photoelectron spectroscopy (XPS) and secondary ne
utral mass spectrometry (SNMS) showed the coating of the microarray by
a SiO2 layer with a thickness gradient across the microarray to be su
ccessful. The gas-detecting properties were examined by exposing the S
iO2-coated microarray to model gas atmospheres. A different gas respon
se for each sensor element was obtained due to the non-uniform SiO2 co
ating resulting in decisive conductivity patterns of the microarray to
be used for gas recognition. (C) 1998 Elsevier Science S.A. All right
s reserved.