| 摘要 |
PROBLEM TO BE SOLVED: To reduce a change in the characteristic of a gas sensor by a method wherein the Mg content of a glass component on the side of a gas-sensitive film in the insulating film of the gas sensor is set at a specific amount. SOLUTION: When an Mg content in an insulating glass is reduced, it is possible to prevent the degradation of a pulse-driven gas sensor. In addition, a large difference exists in the characteristics of the sensors between glasses whose MgO contents are 1wt.% and 5wt.% or 20wt.%. The difference in the characteristic of the sensors is small between the glasses whose MgO contents are 1wt.% and 100wt.ppm. MgO at about 1wt.% exists stably inside the glass so as not to be eluted. An insulating substrate 2 is provided with a heat- insulating glass film 4, with a heater film 6 and with an insulating film 12. The insulating film 12 is constituted of two layers as a lower layer 13 and an upper layer 14. The glass content of the insulating film 12 is preferably at 20 to 100wt.%, the specific Mg content of a gas-sensitive film 16 is set at 2wt.% or lower in the upper layer when the Mg content of a glass component is converted into MgO, preferably at 1.5wt.% or lower, most preferably at 1000wt.ppm or lower, and a contamination with is prevented. |
