Nonvolatile semiconductor memory transistor, nonvolatile semiconductor memory, and method for manufacturing nonvolatile semiconductor memory

摘要

A nonvolatile semiconductor memory transistor included in a nonvolatile semiconductor memory includes an island-shaped semiconductor having a source region, a channel region, and a drain region formed in this order from the substrate side, a hollow pillar-shaped floating gate arranged so as to surround the outer periphery of the channel region in such a manner that a tunnel insulating film is interposed between the floating gate and the channel region, and a hollow pillar-shaped control gate arranged so as to surround the outer periphery of the floating gate in such a manner that an inter-polysilicon insulating film is interposed between the control gate and the floating gate. The inter-polysilicon insulating film is arranged so as to be interposed between the floating gate and the upper, lower, and inner side surfaces of the control gate.

主权项

1. A method for manufacturing a nonvolatile semiconductor memory including a plurality of nonvolatile semiconductor memory transistors each including an island-shaped semiconductor having a hard mask in a upper portion thereof,
each of the island-shaped semiconductors having a source region, a channel region, and a drain region in the order of the source region, the channel region, and the drain region from a side of a substrate, a floating gate and a control gate in the vicinity of the channel region in the order of the floating gate and the control gate from a side of the channel region, the method comprising: forming the island-shaped semiconductors in the substrate; forming a first source line in the substrate; forming insulating films on bottom portions of the island-shaped semiconductors and on the first source line; forming insulating film hard mask sidewalls on outer peripheral walls of the island-shaped semiconductors; forming a floating gate film on the insulating films and on the insulating film hard mask sidewalls; forming the floating gates in the vicinity of the channel regions by etching the floating gate film; exposing a top of the island-shaped semiconductors by etching the insulating film hard mask side walls; and forming doped regions in the island shaped semiconductors to form the drain regions.