Semiconductor memory device and method for manufacturing same

A semiconductor memory device comprising:

• a substrate;
• a conductive layer provided on the substrate;
• a stacked body provided on the conductive layer and including a plurality of electrode layers separately stacked each other;
• a semiconductor pillar portion provided along a stacking direction of the stacked body;
• an interconnect portion provided along the stacking direction of the stacked body and including a first lower surface;
• a semiconductor portion connected with the interconnect portion and the semiconductor pillar portion, the semiconductor portion provided in the conductive layer with an insulating film between the semiconductor portion and the conductive layer, the semiconductor portion including a second lower surface having a height being higher than a height of the first lower surface, the semiconductor portion provided integrally with the semiconductor pillar portion;
• and
• a charge storage film provided between the semiconductor pillar portion and one of the plurality of electrode layers.

A method for manufacturing a semiconductor memory device, comprising:

• forming a sacrificial layer on a substrate;
• forming a conductive layer on the substrate and on the sacrificial layer;
• forming, on the conductive layer, a stacked body including a plurality of first layers separately stacked each other;
• forming a hole penetrating the stacked body and the conductive layer and reaching the sacrificial layer;
• removing the sacrificial layer through the hole to form a cavity;
• forming, on an inner wall of the hole and an inner wall of the cavity, a film including a charge storage film;
• forming a semiconductor portion inside the film including the charge storage film;
• forming a trench penetrating the stacked body, the conductive layer, and the semiconductor portion in the cavity;
• and
• forming, inside the trench, a conductive film to be electrically connected with the semiconductor portion via a side surface of the trench.