Semiconductor storage device and method of manufacturing same

摘要

In a semiconductor storage device a select gate electrode is arranged into a ring shape so as to surround the second impurity regions, and is electrically connected to a word line. A first control gate electrode is arranged into a ring shape on the outer peripheral side of the select gate electrode, and a second control gate electrode is arranged into a ring shape on the inner peripheral side of the select gate electrode. A pair of first and second bit lines corresponding to every row are placed on the memory cells of the device, a first bit line is electrically connected to one of first impurity regions that are adjacent along the row direction, and a second bit line is electrically connected to the other of the first impurity regions that are adjacent along the row direction.

主权项

1. A method of manufacturing a semiconductor storage device comprising:
forming a select gate electrode on a channel region of a substrate via a gate insulating film; forming a gate-isolation insulating film on a surface of a substrate inclusive of the select gate electrode; after a silicon layer is formed on the surface of the gate-isolation insulating film, forming sidewall-shaped first and second control gate electrodes by etching back the silicon layer; forming first and second impurity regions on both sides of a channel region of the substrate in self-aligning fashion; and exposing surfaces of the select gate electrode and first and second impurity regions by removing the gate-isolation insulating film on the select gate electrode and first and second impurity regions; wherein at said forming the first and second impurity regions, the second impurity regions are formed in such a manner that second impurity regions adjacent along the column direction are joined together; and at said forming the select gate electrode, the select gate electrode is formed into a ring shape so as to surround an area in which the second impurity regions are formed.