Semiconductor device and method for manufacturing the same

A semiconductor device, comprising:

• a substrate;
• a stacked body including a plurality of first conductive layers and a plurality of first insulating layers and being provided on the substrate, the first conductive layers and the first insulating layers being provided alternately along a first direction;
• and
• a columnar portion extending through the stacked body in the first direction, the columnar portion including
• a blocking layer provided on the plurality of first conductive layers and on the plurality of first insulating layers in a second direction crossing the first direction,
• a charge storage layer provided on the blocking layer in the second direction,
• a tunneling layer provided on the charge storage layer in the second direction, and
• a semiconductor layer provided on the tunneling layer in the second direction,
• the blocking layer including a third portion and a fourth portion, the fourth portion being positioned between the third portion and the substrate,
• the third portion overlapping a portion of the plurality of first conductive layers in the second direction,
• the fourth portion overlapping another portion of the plurality of first conductive layers in the second direction,
• a dimension in the second direction of the fourth portion being smaller than a dimension in the second direction of the third portion,
• a thickness in the second direction of the fourth portion being greater than a thickness in the second direction of the third portion.

A method for manufacturing a semiconductor device, comprising:

• forming a conductive layer and a first insulating layer alternately on a substrate, a plurality of the conductive layers and a plurality of the first insulating layers being formed;
• exposing side surfaces of the plurality of conductive layers by forming a hole in a stacked body, the stacked body including the plurality of conductive layers and the plurality of first insulating layers, the hole extending in the stacking direction;
• forming a blocking layer on the side surfaces of the plurality of conductive layers;
• forming a charge storage layer on the blocking layer in a first direction crossing the stacking direction;
• forming a tunneling layer on the charge storage layer in the first direction;
• and
• forming a semiconductor layer on the tunneling layer in the first direction,
• the forming of the hole including forming the hole to cause a dimension in the first direction of the hole at a first portion of the stacked body to be larger than a dimension in the first direction of the hole at a second portion of the stacked body, the second portion being provided on the substrate side of the first portion,
• the forming of the blocking layer including forming the blocking layer to cause a thickness of the blocking layer formed at the second portion of the stacked body to be thicker than a thickness of the blocking layer formed at the first portion of the stacked body.