A POLYCRYSTALLINE DIAMOND THIN-FILM-BASED HYDROGEN SENSOR

A new microelectronic gas sensor utilizing polycrystalline diamond fil m in conjunction with a catalytic metal has been developed for hydroge n d etection. The sensor is fabricated in a layered Pd/i-diamond/p-dia mond metal-insulator-semiconductor (MIS) Schottky-diode configuration on a tungsten substrate. The performance of the sensor for H-2 detecti on has been examined in the temperature range 27-300 degrees C. The an alysis of the steady-state reaction kinetics has confirmed that the hy drogen adsorption process is responsible for the barrier-height change in the diamond-based MIS Schottky diode. The use of diamond-film tech nology opens the door to the development of a microelectronic gas sens or that can operate at a wider and higher temperature range than the o nes based on present silicon technology.