Nonvolatile semiconductor storage device
AssigneeKabushiki Kaisha Toshiba
InventorsNaoki YASUDA, Masaru KITO
Life of this patent
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Abstract
According to one embodiment, a control gate is formed on the semiconductor substrate and includes a cylindrical through hole. A block insulating film, a charge storage film, a tunnel insulating film, and a semiconductor layer are formed on a side surface of the control gate inside the through hole. The tunnel insulating film comprises a first insulating film having SiO2 as a base material and containing an element that lowers a band gap of the base material by being added. A density and a density gradient of the element monotonously increase from the semiconductor layer toward the charge storage film.
Claims21
(canceled)
A nonvolatile semiconductor storage device, comprising:
- a stacked structural unit including a plurality of electrode films stacked in a first direction, the electrode films being including a first electrode film;
- a silicon pillar piercing the stacked structural unit;
- a block insulating film provided between the first electrode film and the silicon pillar;
- a charge storage film provided between the block insulating film and the silicon pillar;
- and
- a tunnel insulating film provided between the charge storage film and the silicon pillar,
- wherein the tunnel insulating film includes silicon oxide as a base material and includes an element that lowers a band gap of the base material by being added,
- the tunnel insulating film includes a first point, a second point, and a third point in this order from the silicon pillar toward the charge storage film, and
- a first density of the element at the first point is lower than a second density of the element at the second point and the second density of the element is lower than a third density of the element at the third point.
A nonvolatile semiconductor storage device, comprising:
- a stacked structural unit including a plurality of electrode films stacked in a first direction, the electrode films being including a first electrode film;
- a silicon pillar piercing the stacked structural unit;
- a block insulating film provided between the first electrode film and the silicon pillar;
- a charge storage film provided between the block insulating film and the silicon pillar;
- and
- a tunnel insulating film provided between the charge storage film and the silicon pillar,
- wherein the tunnel insulating film includes silicon oxide as a base material and includes nitrogen,
- the tunnel insulating film includes a first point, a second point, and a third point in this order from the silicon pillar toward the charge storage film, and
- a first density of nitrogen at the first point is lower than a second density of nitrogen at the second point and the second density of nitrogen is lower than a third density of nitrogen at the third point.
Dependencies are inferred from the claim text.