| 摘要 |
PURPOSE:To obtain small-sized, high-reliability sensor at low cost, by using dielectric film having high dielectric constant between the gate and substrate of a gas sensor using MOS transistor. CONSTITUTION:Various oxides having dielectric constant of at least 10 times are provided between silicon substrate 1 and gate to compose the gate construction. For instance, titanium oxide and magnesium oxide of 18 to 25 and titanium oxide film of 70 to 85 are used as the gate oxide film 4. Therefore, in the presence of hydrogen gas, when hydrogen enters a palladium electrode 5, a polarization layer is formed on the gate oxide film boundary surface, and the work function between the palladium and silicon substrate varies, which causes the threshold value to be deviated. Thus, the change in the threshold value may be detected. In this way, a gas sensor having extemely excellent gas detecting sensitivity and response may be obtained. |
