SURFACE DETECTORS FOR ULTRATRACE LEVELS OF TOXIC HYDRIDE GASES

RESEARCHERS ARE DETERMINING THE FEASIBILITY OF DETECTING ULTRATRACE LEVELS OF THE HIGHLY TOXIC HYDRIDE GASES ARSINE AND PHOSPHINE BY TAKING ADVANTAGE OF THE REVERSIBLE INTERACTION OF THESE GASES WITH NOBLE METAL SURFACES. ARSINE AND PHOSPHINE ARE EXTREMELY TOXIC WITH THRESHOLD VALUES FOR HUMAN EXPOSURE AS LOW AS 50 PARTS PER BILLION. THE LOWER DETECTION LIMITS FOR EXISTING TECHNOLOGIES, WHICH ARE SOPHISTICATED, BULKY, EXPENSIVE AND SLOW, ARE ONLY ABOUT 10-30 PARTS PER BILLION, LEAVING TOO SMALL A MARGIN FOR ERROR. IN CONTRAST, THE SURFACE DETECTORS BEING DEVELOPED ARE SIMPLE, SMALL, RELATIVELY INEXPENSIVE, FAST, AND HIGHLY SENSITIVE. PRELIMINARY EXPERIMENTS DEMONSTRATED THAT DETECTION LIMITS MAY BE REDUCED UP TO THREE ORDERS OF MAGNITUDE. THE RESEARCH FOCUSES ON THE DEPENDENCE OF SENSOR RESPONSE ON DETECTOR TYPES, FILM THICKNESS, NATURE OF SUBSTRATE, TEMPERATURE, AND INTERFERENCES, SO THAT ONE METHOD CAN BE SELECTED FOR MORE COMPLETE CHARACTERIZATION AND PROTOTYPE DEVELOPMENT. ULTRATRACE DETECTICAN BE USED WORLDWIDE BY THE SEMICONDUCTOR INDUSTRY AND THEIR CHEMICAL SUPPLIERS FOR IMPROVED SAFETY AND PROCESS CONTROL, AS WELL AS FOR MONITORING HIGHLY TOXIC ARSINE IN NTURAL GAS.