Semiconductor device having a buried insulating layer and method of manufacturing the same

摘要

There is provided a semiconductor device in which the degradation of electric characteristics can be inhibited. A semiconductor substrate (SUB) has a main surface, and a trench (TR) in the main surface. A buried insulating film (Bi) is buried in the trench. The trench has one wall surface (FS) and the other wall surface (SS) which oppose each other. A gate electrode layer (GE) is located over at least the buried insulating film. The trench has angular portions (CP1A,CP2A) which are located between the main surface of at least either one of the one wall surface and the other wall and a bottom portion (BT) of the trench.