Nonvolatile semiconductor storage device
View Patent ↗A semiconductor memory device includes: a semiconductor substrate; a plurality of device isolation regions being disposed in an upper-layer portion of the semiconductor substrate, and dividing the upper-layer portion into a plurality of semiconductor portions extending in a first direction; a plurality of charge storage films which are disposed on one of the plurality of the semiconductor portions and spaced apart from one another in the first direction; a block insulating film disposed covering the plurality of charge storage films; and a word electrode disposed on the block insulating film for each of rows of the plurality of charge storage films arranged in a second direction intersecting the first direction, wherein the block insulating film is disposed continuously in the first direction and in the second direction.
1. A nonvolatile semiconductor storage device comprising:
a semiconductor substrate;
a plurality of device isolation regions being disposed in an upper-layer portion of the semiconductor substrate, and dividing the upper-layer portion into a plurality of semiconductor portions extending in a first direction;
a plurality of charge storage films which are disposed on one of the plurality of the semiconductor portions and spaced apart from one another in the first direction;
a block insulating film disposed covering the plurality of charge storage films; and
a word electrode disposed on the block insulating film for each of rows of the plurality of charge storage films arranged in a second direction intersecting the first direction,
wherein the block insulating film is disposed continuously in the first direction and in the second direction.
2. The nonvolatile semiconductor storage device according to claim 1 , wherein the plurality of charge storage films are spaced apart from one another in the second direction.
3. The nonvolatile semiconductor storage device according to claim 2 , wherein tunnel insulating films are disposed between the plurality of charge storage films and the semiconductor portions.
4. The nonvolatile semiconductor storage device according to claim 1 , wherein the block insulating film is formed of a material having a dielectric constant higher than a material forming the charge storage films.
5. The nonvolatile semiconductor storage device according to claim 1 , further comprising a select gate electrode, wherein
the charge storage films are not arranged between the semiconductor portions and the select gate electrode.
6. The nonvolatile semiconductor storage device according to claim 5 , further comprising a barrier film disposed between semiconductor portions and the select gate electrode and covered by the block insulating film.
7. The nonvolatile semiconductor storage device according to claim 1 , further comprising a select gate electrode, wherein
the charge storage films are arranged between the semiconductor portions and the select gate electrode, and
all of the charge storage films are arranged at regular intervals in the first direction.
8. The nonvolatile semiconductor storage device according to claim 1 , further comprising a low voltage transistor, wherein
the low voltage transistor includes: a gate insulating film in contact with top surfaces of the semiconductor portions; and a gate electrode in contact with a top surface of the gate insulating film.
9. The nonvolatile semiconductor storage device according to claim 1 , wherein a top surface of each of the plurality of device isolation regions is lower than a top surface of the block insulating film.
10. The nonvolatile semiconductor storage device according to claim 1 , wherein a top surface of the block insulating film between the plurality of charge storage films is lower than a top surface of the block insulating film above the charge storage films.