NONVOLATILE SEMICONDUCTOR STORAGE DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor storage device improved in reliability of a gate insulation layer, and a data retention characteristic.

SOLUTION: This nonvolatile semiconductor storage device 100 is provided with: a memory columnar semiconductor layer 38 extending in the vertical direction with respect to a semiconductor substrate Ba; first to fourth word line conductive layers 32a-32d formed through charge storage layers 36 on the sidewall side of the memory columnar semiconductor layer 38; and first to fifth inter-word-line insulation layers 31a-31e formed on the upper and lower sides of the first to fourth word line conductive layers 32a-32d. The sidewalls of the first to fourth word line conductive layers 32a-32d on the memory columnar semiconductor layer 38 side are formed to tilt in a direction separating from the center axis of the memory columnar semiconductor layer 38 as they move from the upper side to the lower side. The sidewalls of the first to fifth inter-word-line insulation layers 31a-31e on the memory columnar semiconductor layer 38 side are formed to tilt in a direction approaching the center axis of the memory columnar semiconductor layer 38 as they move from the upper side to the lower side.

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