Ga2O3 thin film for oxygen sensor at high temperature

Gallium oxide thin film has properties of n-type semiconductor and it is st able at high temperature. The resistivity of Ga2O3 changes with the concent ration of oxygen in the thin film. An oxygen sensor was made on the basis o f this principle. Gallium oxide thin film was deposited on the Si substrate from a sintered powder target by a rf magnetron sputtering using Ar as the sputtering gas. The sputtering condition is a very important factor to con trol the oxygen content of the Ga2O3 thin film and hence the response chara cteristics of the sensor. In this present paper, an attention was paid on t he sputtering pressure of Ar during the film deposition. It has been found that electrical conductivity, gas sensitivity and rising response time of t he thin film depends on sputtering pressure of Ar during the deposition pro cess. It has also been clarified that gallium oxide thin film deposited in lower sputtering pressure shows better electrical conductivity and rising r esponse time. whereas the thin film deposited in high sputtering pressure s hows higher gas sensitivity The difference in characteristics of the deposi ted thin films may be considered due to the surface structure as revealed f rom the AFM observation. (C) 2001 Elsevier Science B.V. All rights reserved .