Patent ID: 7057229
Filing Date: 2006-06-06
Classification: H01L

Abstract:
1. A semiconductor nonvolatile memory device for storing multi-bit data, comprising: a memory cell, the memory cell including: a source region and a drain region which are formed at a surface of a semiconductor substrate; a gate insulator film and a control gate which are formed on a channel region between the source region and the drain region; and a nonconductive trap gate in the gate insulator film; wherein the memory cell has, at the surface of the semiconductor substrate, an indentation portion extending from a position in the vicinity of the drain region in the channel region to the drain region, wherein charges are trapped to the trap gate on the indentation portion, and wherein a region of a type opposite to the source region is formed between the source region and the channel region, and the region of a type opposite to the source region extends to the indentation portion and is not formed between the source region and channel region in the indentation portion.