Pd-MOS structures with holes in the gate metal have been prepared for detecting arsine, and investigated in a flow system. The samples show a reversible decrease of threshold voltage on admixtures of arsine to an air stream (temperature range 350 K to 470 K). A change of threshold voltage of 34 mV is found for 0.1 ppm arsine in air (T=433 K). For arsine concentrations of 2.5 ppm, a response time of 40 s and a recovery time of 300 s are observed at 450 K. The response of the same structures to small concentrations of H2 has also been investigated. Sensitivity and response are comparable to the results found for arsine. This similarity points to a decomposition of arsine at the Pd surface, with subsequent diffusion of hydrogen to the metal-oxide interface. (IMS)
