Non-volatile semiconductor storage device and method of manufacturing the same
A non-volatile semiconductor storage device has a plurality of memory strings with a plurality of electrically rewritable memory cells connected in series. Each of the memory strings includes: a first columnar semiconductor layer extending in a direction perpendicular to a substrate; a charge accumulation layer formed on the first columnar semiconductor layer via a first air gap and accumulating charges; a block insulation layer contacting the charge accumulation layer; and a plurality of first conductive layers contacting the block insulation layer.
1. A non-volatile semiconductor storage device comprising a plurality of memory strings with a plurality of electrically rewritable memory cells connected in series, and a selection gate transistor controlling whether to conduct current to the memory strings, wherein
each of the memory strings comprises:
a first columnar semiconductor layer extending in a direction perpendicular to a substrate;
a charge accumulation layer formed on the first columnar semiconductor layer via a first air gap and accumulating charges;
a block insulation layer contacting the charge accumulation layer;
a plurality of first conductive layers contacting the block insulation layer; and
a first sealing/insulating layer formed to seal the top of the space made by the first air gap,
the charge accumulation layer being continuously formed over the plurality of memory cells,
the selection gate transistor comprises:
a second columnar semiconductor layer formed in contact with the top or bottom surface of the first columnar semiconductor layer and extending in a direction perpendicular to the substrate; and
a second conductive layer formed along the second columnar semiconductor layer,
the first sealing/insulating layer is formed in a position different from a position between the second columnar semiconductor layer and the second conductive layer.
2. The non-volatile semiconductor storage device according to claim 1 ,
the second conductive layer is formed on the second columnar semiconductor layer via a second air gap.
3. The non-volatile semiconductor storage device according to claim 2 , wherein
the selection gate transistor further comprises a second sealing/insulating layer formed to seal the top of the space made by the second air gap.
4. The non-volatile semiconductor storage device according to claim 1 ,
a gate insulation layer contacting the second columnar semiconductor layer, the second conductive layer is contacting the gate insulation layer, and the gate insulation layer has a second air gap or a seam.
5. A non-volatile semiconductor storage device comprising a plurality of memory strings with a plurality of electrically rewritable memory cells connected in series, and a selection gate transistor controlling whether to conduct current to the memory strings, wherein
each of the memory strings comprises,
a first columnar semiconductor layer extending in a direction perpendicular to a substrate,
a charge accumulation layer formed around the first columnar semiconductor layer and accumulating charges,
a block insulation layer contacting the charge accumulation layer, and
a plurality of first conductive layers contacting the block insulation layer,
the charge accumulation layer being continuously formed over the plurality of memory cells; and
the selection gate transistor comprises,
a second columnar semiconductor layer extending in a direction perpendicular to a substrate, and
a second conductive layer formed on the second columnar semiconductor layer via a second air gap; and
a second sealing/insulating layer configured to seal the top of the space made by the second air gap and formed in a position different from a position between the first columnar semiconductor layer and the first conductive layer.