Semiconductor sensors for the detection of fluorocarbons, fluorine and hydrogen fluoride

The sensitivity of metal-insulator-semiconductor structure gas sensors base d on silicon or silicon carbide to different fluorine-containing gases was studied in the temperature range 20-530 degrees C. Silicon based gas sensor s could be used for the determination of fluorine and hydrogen fluoride at room temperature. The sensitivity to fluorine is 28.0+/-0.5 mV/lg(p(F-2)), the sensitivity to HF is 44.4+/-1.6 mV/(p(HF)), and the detection is about 10 ppb in both instances. High temperature silicon carbide sensors can be a pplied for the determination of fluorine and fluorocarbons (CF3CH2F, CF3CCl 3, CF3CH2Cl, CHClF2, CCl2F2, CCl3F) up to 530 degrees C. The sensor signal for fluorocarbon concentration measurements demonstrates a Nernstian concen tration dependence. The detection limit for these gases is ca. 10 ppm. (C) 1999 Elsevier Science B.V. All rights reserved.