| 摘要 |
PURPOSE:To eliminate the leak current during detection of the OFF state and to improve the accuracy of detection in the OFF state, by providing either a drain or a source with a thin insulation film (tunnel insulation film) formed between an impurity region and an electrode. CONSTITUTION:A tunnel oxide film 45 is provided between an impurity region 71 in an operating region 31 and an electrode 92. For forming this tunnel oxide film 45, impurity regions 71 and 72 are initially provided and only the surface of the region 71 in the operating region 31 is selectively oxidized before electrodes 91-94 are formed. The tunnel oxide film 45, having certain insulating properties, becomes completely insulating state when a depletion layer is spread between the source and the drain. When there is no depletion layer, however, the tunnel oxide film 45 conducts current and causes no problem for the original purpose of sensing ON or OFF between the source and the drain. Further, no leak current is caused in the detection of OFF, the sensing accuracy in the OFF state is improved. |
