Semiconductor device and manufacturing method thereof

A semiconductor device, comprising:

• a stacked body including a plurality of conductive layers that are stacked and spaced from each other in a first direction, the stacked body further having first and second areas arranged along a second direction intersecting the first direction;
• an insulating portion extending along the first and second directions in the first and second areas and dividing the conductive layers in a third direction intersecting the first and second directions;
• a plurality of first columnar portions each extending along the first direction in the first area and including a first semiconductor layer, wherein a plurality of memory cells are formed at intersections between the conductive layers and the first semiconductor layer;
• a plurality of second columnar portions each extending along the first direction in the second area and including an insulator;
• a plurality of third columnar portions each extending along the first direction in the second area and including a second semiconductor layer;
• and
• a plurality of contacts each extending along the first direction in the second area and electrically connected to one of the conductive layers, wherein
• the second columnar portions are on both sides of the insulating portion in the third direction.