| 摘要 |
PURPOSE:To improve the withstand voltage and to reduce the injection of hot carrier by providing reverse conductive type layers to source and drain on the surface layer of a channel forming region, and providing the same conductive type layer as an impurity density lower than source and drain between the layer and a substrate. CONSTITUTION:n<+> Type source and drain 32a, 32b, and a gate electrode 34 are respectively formed on a p type Si substrate 31 and a gate oxidized film 33. Further, a p type layer 36 is provided on a channel region, and an n type layer 35 is formed between a layer 36 and a substrate 31. In this construction, even if a gate voltage is raised, an n type channel is not generated at the layer 36, the channel is sealed by the layer 35 irrespective of the magnitude of a gate voltage, and operated in a buried channel type in the all range of the gate voltage. Accordingly, the withstand voltage can be improved, the injection of hot carrier can be reduced, and the mobility of the hot carrier can be increased, and these effects are very effective for microminiaturization of a semiconductor device. |
