Ga2O3 thin films for high-temperature gas sensors

Gallium oxide thin films have promising properties for high-temperature-stable and n-type semiconducting properties at high temperatures above 600 degrees C. The film function of gallium oxide is considered to detect oxygen as hulk-control-type sensors over 900 degrees C, and also to detect reducing gases as surface-control-type sensors in the temperature range of 500 degrees-850 degrees C. Gallium oxide thin films were deposited by rf magnetron sputtering. Annealing process was performed to improve the film crystallinity. Crystallization and composition analysis were confirmed with XRD and AES measurements. It was found that oxygen content in gallium oxide is deficient the sputtered film. Moreover, crystallization and electrical conductivity are controllable by sputtering conditions such as substrate temperature, gas pressure and others. (C) 1999 Elsevier Science B.V. All rights reserved.