Semiconductor device and method of fabricating the same
A semiconductor device includes a semiconductor layer, a charge storage layer provided on a surface of the semiconductor layer via a tunnel insulating film, and an electrode layer provided on a surface of the charge storage layer via a block insulating film. The tunnel insulating film includes a plurality of first silicon oxynitride films which are provided between the semiconductor layer and the charge storage layer. The tunnel insulating film further includes a silicon oxide film provided between the first silicon oxynitride films and/or a second silicon oxynitride film which is provided between the first silicon oxynitride films and has an oxygen concentration higher than an oxygen concentration in the first silicon oxynitride film.
1. A semiconductor device, comprising:
a stacked body including a plurality of insulating layers and a plurality of electrode layers that are alternately stacked in a first direction;
a semiconductor layer extending through the stacked body in the first direction;
a charge storage layer disposed on a surface of the semiconductor layer with a tunnel insulating film between the charge storage layer and the semiconductor layer; and
a block insulating film between the charge storage layer and one of the electrode layers, wherein
the tunnel insulating film includes:
a first silicon oxynitride film being in contact with the semiconductor layer;
a first oxide-rich film being in contact with the first silicon oxynitride film and having an oxygen concentration higher than an oxygen concentration in the first silicon oxynitride film;
a second silicon oxynitride film being in contact with the first oxide-rich film;
a second oxide-rich film being in contact with the second silicon oxynitride film and having an oxygen concentration higher than the oxygen concentration in the first silicon oxynitride film; and
a third silicon oxynitride film being in contact with the second oxide-rich film.
2. The semiconductor device according to claim 1 , wherein
a thickness of each of the first and second oxide-rich films is thinner than a thickness of each of the first through third silicon oxynitride films.
3. The semiconductor device according to claim 1 , wherein
a thickness of each of the first and second oxide-rich films is thinner than a thickness of each of the first through third silicon oxynitride films.
4. The semiconductor device according to claim 1 , wherein
a thickness of each of the first and second oxide-rich films is 0.1 nm or more, and 2.0 nm or less.
5. The semiconductor device according to claim 1 , wherein
a thickness of each of the first and second oxide-rich films is 0.1 nm or more, and 2.0 nm or less.
6. The semiconductor device according to claim 1 , wherein
a distance between the first or second oxide-rich film and the semiconductor layer is shorter than an electron tunnel distance and a hole tunnel distance from the semiconductor layer.
7. The semiconductor device according to claim 1 , wherein
the tunnel insulating film further includes a third silicon oxynitride film provided between the first silicon oxynitride films and having a nitride concentration higher than a nitride concentration in the first silicon oxynitride films.
8. The semiconductor device according to claim 7 , wherein
the third silicon oxynitride film is provided on the side of the silicon oxide film or the second silicon oxynitride film toward the charge storage layer, and contacts a surface of the silicon oxide film or the second silicon oxynitride film.
9. The semiconductor device according to claim 1 , wherein
the tunnel insulating film further includes a third silicon oxynitride film provided between the first silicon oxynitride films and having a nitride concentration higher than a nitride concentration in the first silicon oxynitride film.
10. The semiconductor device according to claim 9 , wherein
the third silicon oxynitride film is provided on the side of the silicon oxide film or the second silicon oxynitride film toward the charge storage layer, and contacts a surface of the silicon oxide film or the second silicon oxynitride film.
11. The semiconductor device according to claim 1 , wherein the tunnel insulating film also extends through the stacked body in the first direction.
12. The semiconductor device according to claim 1 , wherein each of the first through third silicon oxynitride films and the first through second oxide-rich films includes SiON.