| abstract |
It is an object to provide a semiconductor device capable of holding multibit information in one memory cell also when scaling for a nonvolatile memory progresses, and a method of manufacturing the semiconductor device. A trench (TR 1 ) is formed in a channel portion of an MONOS transistor. Then, a source side portion and a drain side portion in a silicon nitride film ( 122 ) of a gate insulating film ( 120 ) which interpose the trench (TR 1 ) are caused to function as first and second electric charge holding portions capable of holding electric charges (CH 1 ) and (CH 2 ). In the case in which the electric charges (CH 1 ) are trapped and the electric charges (CH 2 ) are then trapped, thus, a portion ( 130 a ) of a gate electrode ( 130 ) in the trench (TR 1 ) functions as a shield. If a fixed potential is given to the gate electrode ( 130 ), the second electric charge holding portion is not influenced by an electric field (EF 1 ) induced by the electric charges (CH 1 ) so that the trapping of the electric charges (CH 2 ) is not inhibited. |