| 摘要 |
PURPOSE:To obtain a function of adding to a constant current a current proportional to a difference when a voltage exceeds the prescribed value in case that a constant current flows continuously when a gate voltage is zero or very low level by employing a part of a region interposed between a drain part and a source part of an IGFET as a gate and the residue as a depletion layer. CONSTITUTION:A drain part 2 and a source part 3 are diffused at the prescribed interval on the surface side of an Si substrate 1, and a range that does not reach the entire width W of the region 4 interposed between the part 2 and the part 3 is used as a gate 5. Then, the residue is used as a depletion layer 6 of high injection density, and a depletion layer is not provided under the gate 5 made of a gate oxidized film 5a and the gate electrode 5a disposed above the film 5a. In this mannr, the layer 6 part is operated as a zero bias depletion type MOSFET, and the gate 5 part is operated as an enhancement type MOSFET. |
