| 摘要 |
PROBLEM TO BE SOLVED: To prevent lowering of impurity concentration at an element separation end, and improve characteristics by forming an opening part reaching a first insulating film near the border of a second insulating film to a mask layer, and forming an impurity region at a substrate front-side of the opening part. SOLUTION: A gate electrode 112 comprising a conductive polysilicon is provided, in an active region separated by an silicon oxide film (second insulating film) 105 which is embedded in the channel provided in a p-type silicon semiconductor substrate 101, with a gate oxide film 107 in between. In a region around the lower part of the gate electrode 112 of the active region, a source/ drain region 108 where an n-type impurity is doped and a contact 109 which electrically connects the source/drain region 108 to a wiring layer 110 are provided, with the upper layer covered with an inter-layer insulating film 111. Since an impurity region 106 where an n-type impurity is doped is formed at the border part to the insulating film 105 near the active region surface, the threshold value of a transistor at the border part to an element separation region is prevented from falling, to improve reliability.
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