| 摘要 |
PURPOSE: To prevent catalyst from being polluted by environmental pollutant such as sulfur compound, etc., so as to maintain the stability of a catalyst sensitization type semiconductor gas detection element for a long time by adding molybdenum or molybdenum compound to the gas detection element. CONSTITUTION: An almina substrate 1 is prepared as insulating substrate, and a comb type metal electrode 2 is formed on the substrate 1. Then, after a tin thin film is formed on its top face, it is heat-treated at a predetermined temperature in the air to obtain a thin film-like gas sensitive body 3 made of tin oxide. Furthermore, after platinum catalyst 4 is formed on the sensitive body 3, molybdenum trioxide 5 is formed. Lastly, it is held at a predetermined temperature for aging treatment so as to stabilize the resistance value of the element. A vacuum vapor deposition method, etc., is used as a method for forming a mass film. The amount of catalyst to be added is appropriately selected depending on the type of gas to be detected and a material of catalyst. For example, the thickness of the mass film is 100Åor less here. Oxide (for example, MoO2 , etc.), halogen compound, etc., are used as molybdenum compound.
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