Nonvolatile semiconductor memory device
AssigneeKabushiki Kaisha Toshiba
InventorNaoki Yasuda
Life of this patent
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Abstract
A nonvolatile semiconductor memory device includes a charge storage layer on a first insulating film, a second insulating film which is provided on the charge storage layer, formed of layers, and a control gate electrode on the second insulating film. The second insulating film includes a bottom layer (A) provided just above the charge storage layer, a top layer (C) provided just below the control gate electrode, and a middle layer (B) provided between the bottom layer (A) and the top layer (C). The middle layer (B) has higher barrier height and lower dielectric constant than both the bottom layer (A) and the top layer (C). The average coordination number of the middle layer (B) is smaller than both the average coordination number of the top layer (C) and the average coordination number of the bottom layer (A).
Claims20
A nonvolatile semiconductor memory device comprising:
- a semiconductor region;
- a first insulating film on the semiconductor region;
- a charge storage layer on the first insulating film;
- a second insulating film on the charge storage layer;
- and
- a control gate electrode on the second insulating film,
- wherein the second insulating film includes a bottom layer (A) in contact with the charge storage layer, a top layer (C) in contact with the control gate electrode, and a middle layer (B) between the bottom layer (A) and the top layer (C),
- the middle layer (B) comprises (SiO2)x(Si3N4)1-x (0.75≦x≦1),
- the bottom layer (A) comprises one of Al-oxide, Al-oxynitride, Al-silicate, Al-nitride-silicate, Hf-oxide, and Al—Hf-oxide, and
- the top layer (C) comprises one of Al-oxide, Al-oxynitride, Al-silicate, Al-nitride-silicate, and Si-nitride.
A nonvolatile semiconductor memory device comprising:
- a semiconductor region;
- a first insulating film on the semiconductor region;
- a charge storage layer on the first insulating film;
- a second insulating film on the charge storage layer;
- and
- a control gate electrode on the second insulating film,
- wherein a composition, a dielectric constant and a barrier height of the second insulating film vary continuously in a film thickness direction, and
- the second insulating film comprises SiO2 at a center in the film thickness direction, and comprises Al2O3 at a top and a bottom in the film thickness direction.
Dependencies are inferred from the claim text.