| 摘要 |
PURPOSE:To obtain a gas sensor especially excellent in gas selectivity, by a method wherein an ultra-fine particle film comprising metal oxide of which the greater part of crystals are oriented to a specific surface direction is formed on a substrate and an electrode is formed on said film. CONSTITUTION:When the division ratio obtained by dividing the peak intensity of the diffraction surface of an X-ray chart by the relative intensity of the same surface of an ASTM card is calculated and the ratio A/B of the max. value A and the min. value B of said ratio is defined as an orientation characteristic, a sensor film 11 being an ultra-fine particle film occupied by metal oxide particles each having an average particle size of 40-200Angstrom in an amount of 95% or more by wt. of the whole film and packed in 27-74% by ratio of the theoretical density of the particle is formed on a substrate 9 made of Al2O3 having a gold comb shaped electrode 10 formed thereon under gas pressure of 8X10<-2>torr or more while adjusting the temp. of said substrate 9 to a low temp. almost equal to a liquid nitrogen temp. After the film is formed, heat treatment is performed at a temp. 100-300 deg.C higher than the operation temp. of the gas sensor. The electrode 10 may be provided on the film 11 formed on the substrate 9. |
