| 摘要 |
PURPOSE:To obtain a gas sensor element quick in response at room tempera- ture and consumption low electricity through utilization of battery reaction by installing ZrO2 film with CaO added as a solid electrolyte film at the gate section of a MOS type FET construction. CONSTITUTION:A metallic gage electrode 4 is formed on a P type Si wafer 1 with n type source drain layer 2, field oxide (SiO2) layer 3 and Ni and a ZrO2 layer doped with CaO as a solid electrolyte 5 is provided to cover the electrode 4, and a grid-mesh type electrode 6 of Pt, etc. is formed on the electrolyte layer 5 to produce a gas sensor element. Characteristic voltage according to a gas to be sensed, for example, 850WV for O2 gas or 400WV for SO2 gas is applied between the electrodes 4 and 6 to operate the lower FET for sensing a gas to be sensed. With this construction a thin film battery of Ni/ZrO2(CaO)/Pt is formed, and a highly reliable sensing element that can be driven in a high resistance route at low voltage, and furthermore quick in response and operable at room temperature without a heating circuit can be obtained. |
