Auger and SIMS study of segregation and corrosion behaviour of some semiconducting oxide gas-sensor materials

Abstract The influence of corrosive gases (H 2 , CO, NO, Cl 2 , SO 2 ) on the composition of sputtered polycrystalline StTiO 3 , CeO 2 and Ga 2 O 3 thin films was studied. Auger electron spectroscopy (AES) and secondary ion mass spectroscopy (SIMS) were applied for studying the depth profiles of atomic composition of the thin films, treated for several hundred hours at 800 °C in diluted (20 ppm, 5%) corrosive gases. SrTiO 3 was strongly attacked by Cl 2 and SO 2 . During the Cl 2 treatment the layer thickness was reduced and the structure altered near the grain boundaries. SO 2 treatment caused a new surface phase formation (probably SrO). the Ga 2 O 3 layer had a fast reaction with Cl 2 giving rise to volatile Ga products but the other corrosive gases had no deteriorating effect on the layer. CeO 2 proved to be the most resistant to all the gases mentioned above.