THIN-FILM SNO2 SENSOR ARRAYS CONTROLLED BY VARIATION OF CONTACT POTENTIAL - A SUITABLE TOOL FOR CHEMOMETRIC GAS-MIXTURE ANALYSIS IN THE TLVRANGE

The selectivity of SnO2 thin-film gas sensors can be modulated by chan ging the contact areas of the contact electrodes. The investigated SnO 2 arrays have been structured with two mask steps only. Gas mixture an alysis in the German threshold limit value (TLV) range has been perfor med with an integrated thin-film sensor array using principal componen t regression (PCR) analysis. As an example, NO2, CO, CH4 and H2O mixtu res in air have beer, analyzed. In this case additional doping materia ls, catalysts, temperature gradients, etc., to enhance selectivity are not necessary. (C) 1997 Elsevier Science S.A.