PROCESS AND APPARATUS FOR DETERMINING THE QUALITY OF IMPURITIES IN A GAS BY CHROMATOGRAPHY IN GAS PHASE AND UTILIZATION FOR MEASURING THE QUANTITY OF DOPING IMPURITIES IN SILANE

摘要

The apparatus for determining the quantity of impurity in a gas by chromatography in gas phase comprises a device for cryogenically trapping impurities, which is provided with a column filled with granular particles of a product capable of adsorbing the impurities, refrigerating means capable of keeping the column at low temperature during passage of the gas loaded with impurities and reheating means for an ulterior desorption; a first chromatographic adsorber in gas phase intended for a preliminary analysis and provided with a filling column for each impurity; a device for the cryogenic recentering of the purities, which is provided with a capillary column, refrigerating means capable of keeping the column at low temperature during the passage of a carrier gas which has gone through the first chromatographic adsorber, and desorption reheating means; and a second chromatographic adsorber in gas phase provided with a capillary column, a detection device being mounted at the outlet.