Semiconductor device and method for manufacturing the same
AssigneeKabushiki Kaisha Toshiba
InventorsTetsuya Kai, Ryuji Ohba, Yoshio Ozawa
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Abstract
A semiconductor device includes a semiconductor substrate, and a nonvolatile memory cell provided on the semiconductor substrate, the nonvolatile memory cell including a tunnel insulating film provided on a surface of the semiconductor substrate, the tunnel insulating film including semiconductor grains, the semiconductor grains included in both end portions of the tunnel insulating film having smaller grain size than the semiconductor grains included in other portions of the tunnel insulating film, a charge storage layer provided on the tunnel insulating film, an insulating film provided on the charge storage layer, and a control gate electrode provided on the insulating film.
Claims20
A semiconductor device comprising:
- a semiconductor substrate;
- and
- a nonvolatile memory cell provided on the semiconductor substrate,
- the nonvolatile memory cell comprising:
- a tunnel insulating film provided on a surface of the semiconductor substrate, the tunnel insulating film including semiconductor grains, the semiconductor grains included in both end portions of the tunnel insulating film having smaller grain size than the semiconductor grains included in other portions of the tunnel insulating film;
- a charge storage layer provided on the tunnel insulating film;
- an insulating film provided on the charge storage layer;
- and
- a control gate electrode provided on the insulating film.
A method for manufacturing a semiconductor device, the semiconductor device comprising a semiconductor substrate, and a nonvolatile memory cell provided on the semiconductor substrate, the nonvolatile memory cell comprising a tunnel insulating film provided on a surface of the semiconductor substrate, the tunnel insulating film including semiconductor grains such that the semiconductor grains included in both end portions of the tunnel insulating film have smaller grain size than the semiconductor grains included in other portions of the tunnel insulating film, a charge storage layer provided on the tunnel insulating film, an insulating film provided on the charge storage layer, and a control gate electrode provided on the insulating film,
- the method comprising:
- forming a tunnel insulating film on a surface of the semiconductor substrate, the tunnel insulating film including semiconductor grains which have approximately same grain size;
- and
- selectively decreasing grain size of the semiconductor grains included in the both end portions of the tunnel insulating film.
Dependencies are inferred from the claim text.