| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device that can suppress the formation of a parasitic MOSFET at the end of an active region and can be operated with desired characteristics. SOLUTION: In the semiconductor device, grooves 2 are formed on the surface of a substrate 1 and silicon oxide film 9 which make groove element isolation are buried in the grooves 2. The silicon oxide films 9 do not have shapes where the surfaces of the films 9 become smaller in height from the main surface 1S of the substrate 1. A channel impurity layer 10 which controls the threshold voltage of a MOSFET is formed in the main surface 1S of the substrate 1. The layer 10 is composed of a P-type layer and contains an impurity at a concentration higher than that of the impurity in the substrate 1. The first portions 10A of the channel impurity layer 10 are formed along the side faces 2S of the grooves 2 near the opened ends of the grooves 2 and positioned in source-drain layers 6, more specifically, in N+-type layers 6B. The second portion 10B of the impurity layer 10 is formed at a position deeper than those of the first portions 10A. On the main surface 1S of the substrate 1, in addition, a gate-insulating film 4 and a gate electrode 5 are formed. |
