Microelectronics MIS gas-sensitive structures with enhanced stability

The stability of microelectronics Metal-lnsulator-Silicon (MIS) gas-sensitive structures with Pd and Pd/Cu composite metal layers have been studied and compared. The metal films were obtained by magnetron deposition in Ar plasma. Detailed investigations of surface morphology and chemical composition of the layers by SEM and AES depth profiling have been performed too. A shift of the flat band voltage (/spl Delta/V/sub js/), obtained from the measurements of capacitance voltage characteristics was used as a response of a MIS structure on the supplying of gas pulses. Such gases as hydrogen, humidity, and air (oxygen) were tested by the sensors. The kinetics of the responses was studied experimentally and compared with the results of a computer simulation. To investigate the stability of the MIS structures they were subjected to an accelerated artificial aging by annealing in air at 100-250/spl deg/C during 0.3-3 h. It was found that MIS sensors with Pd/Cu composite layer demonstrate higher sensitivity to hydrogen and higher stability under artificial aging than similar structure with Pd layer only.