X-RAY PHOTOEMISSION AND AUGER-ELECTRON SPECTROSCOPY ANALYSIS OF FAST RESPONDING ACTIVATED METAL-OXIDE-SILICON CARBIDE GAS SENSORS

Platinum-silicon dioxide-silicon carbide, MOSiC, sensors are possible to operate at high temperatures and show a gas sensitivity pattern whi ch is of interest for many applications including exhaust gases from c ar engines. The introduction of a buffer layer of tantalum silicide be tween the metal and the silicon dioxide resulted, after an annealing s tep, in a very good adhesion of the gate contact and fast responding s ensors with improved signal stability. Depth profiling using X-ray pho toemission and Auger electron spectroscopy showed that the annealing s tep converts the tantalum silicide to a mixed phase predominantly cont aining tantalum pentoxide. Tantalum silicide as well as platinum silic ide are also present in the metal-oxide interface region. (C) 1997 Els evier Science S.A.