| 摘要 |
PURPOSE:To prevent the occurrence of leakage and latch-up and thereby to secure a normal operation, by a construction wherein an element region inside an insular region is surrounded by a P-type high-concentration impurity layer, while an oxide film having the same film thickness as a gate oxide film is provided on the insular region except the element region and under a gate electrode. CONSTITUTION:The title device has a structure wherein an annular P<+> layer 6 is so provided as to surround an element region 3a separately therefrom and one end of a gate electrode 8 overlaps partially with the P<+> layer 6, while an oxide film 9 having the same film thickness as a gate oxide film 7 is provided on an insular region 3 except the element region 3a and under the gate electrode 8. Therefore, a thick parasitic transistor of the oxide film is not formed in the end portion of a gate. When radiations are applied, accordingly, the leakage due to the application of radiations can be prevented from occurring between source and drain regions 4 and 5, as is the case with prior art, and therefore a transistor operates normally.
|
